Congrates on the degree; congrates for working through your depression; and congrates on the job. None of those things are easy to accomplish and you have done them all!
I want to pick up on something you said.
I was excited when I initially got offered the job but then the next day the reality kicked in...I am scared of being somewhere full time in case I want to run away and I am now worried I have done the wrong thing.
Reality kicked in or your thoughts? Thoughts are like snakes slithering around your head. "What if this What if that?" You start imagining what COULD happen and before you know it you are reacting as though it HAS happened.
Having such a few traumatic years you are bound to imagine the worst. However imaging the worst means you are responding that way and before you know it, your back in that situation again.
There is a reason why YOU rather than others got this job. PERHAPS you were the best person for it. Perhaps if you get into difficulty you will still be supported; perhaps a challenging job with young people is what you need. All of those statements probably havent really occured to you before because of your thought patterns.
If the job turns out to be to much for you you can always leave but how will you know until you try? Through your conselling you must have learnt some skills. Maybe you need to take another look from another perspective.
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