How do I deal with emotions my psycologist has unlocked?

Your pain likely ‘flags’ that you have a lot of feelings about what happened to you that have not been ‘processed’. Processing in psychological terms, means allowing yourself to feel the feelings and to make sense and meaning out of what happened to you, to realise the impact it is had and then to find ways to heal from it (a little like cleaning out a wound). You are right also that if you are overwhelmed with painful emotions when you ‘touch’ the pain you may be left feeling lost and raw. The good news is that if you've found a good therapist and you talk to him about how you are feeling he will help you to develop strategies to manage and ‘contain’ the feelings so that you can then successfully ‘process’, (i.e. clean the wound and heal it). In therapy circles we talk about a therapeutic window. This means finding a way to process your pain that doesn't overwhelm you (i.e. that doesn't overshoot the window), whilst at the same time making sure that you are dealing with the issues and moving forwards (i.e. not undershooting the window). So, start by speaking to your therapist, perhaps you could send him the email you've just send to Healthshare (of course directed to him) if you are finding talking face to face too difficult at this stage. Best of luck, and congratulations for taking the courageous step of moving towards healing.

I am happy that you have reached out for help which means you are half way there. Sometimes therapy can open a can of worms you never realised you had. It is important to tell your therapist how you felt after your last session. He might suggest some techniques to contain the session to the present or to come more often or to be able to contact him between sessions depending on how he works therapeutically. Sometimes you do experience feeling worse before you feel better.
However the main thing is if you have a good rapport with your therapist you will feel comfortable talking to him about the last session and what it brought up for you.

Good healing will take place just give it time.

You are doing so well to go for help.

Given the experiences you had as a child sound terribly traumatic, and that you had to suppress these, and pretend everything was okay, it is understandable that revisiting these events will cause strong emotional reactions, and it is okay to feel overwhelmed sometimes. I would also be evaluating you for Post-traumatic stress disorder, or Complex Post-traumatic stress disorder.  Anxiety is one of the most common presentations for these, and inability to make decisions is a key feature of generalised anxiety.

The two gold standard Treatments for PTSD are Trauma-focused CBT and EMDR.  Both have good efficacy, and evidence of maintained outcomes at long-term follow-up.  I think the research says that EMDR Seems to have more long-term effect.  

Revisiting trauma can be highly detrimental if not done in the correct manner.  I would not advise clients to be sitting thinking about these things by themselves, without structure, guidance, and without at least FIRST being shown the techniques to calm their responses.  

It is good that your psychologist has identified the developmental nature of your symptoms. If the emotions are ones that stem from childhood experiences, it is important that your psychologist has some understanding of the developmental stages you were going through when these events occurred, and how this may have affected your development into adulthood.

Good on you for seeking assistance -- you need to go back to your psychologist and be really frank with them about your concerns.  Your caution is completely reasonable, however don't give up just because it's painful, but rather make sure that you have been given the right techniques and support to manage your responses.  

If after speaking with the psychologist over your feelings of not being able to process these feelings and emotions by yourself, and he still asks you to do this on your own is of concern to me.  Go with your gut feeling and don't do it until you fee safe to be able to do this, preferably with someone at your side helping you.

Have you thought of asking what other methods he has that can help you with your past feelings from childhood without needing to do this on your own?  If you are not happy with his response tell him and ask him to on-refer you to someone else, or go back to your doctor to get another referral. 

It sounds as if you missed out on being taught some skills in early childhood. So you are bound to feel vulnerable. There is always time to make up for that loss by learning new skills, but your feelings and emotions require releasing, now you can feel they have surfaced.  Eye Movement Desensitisation and Reprocessing (EMDR) as mentioned above is one method.  Emotional Freedom Technique (EFT) is another, both of which I would find helpful to use in the hypnosis trance state (without needing to go back to the original event(s)).  But make sure the therapist you use knows what they are doing.

I agree with what Darren and Brunhilde wrote about EMDR.

I used to go to a weekly therapy group for people with mood disorders. A fellow group member with PTSD reported that he found EMDR very helpful. He stressed that it is important to find a mental health professional with experience of using that approach - he said that he had a poor experience with somebody who did not know much about it.

This might be worth talking about with your psychologist - he should be able to suggest a colleague who has experience of using EMDR with his/her clients.

All the best.