Emily,

You said I’m in my mid 30s and feel as though I haven’t been allowed to start my adult life yet. 

You must feel so much stuck and in despair about your situation.  It sounds like you are in severe depression if you are crying all the time, and being in constant state of anxiety, panic, paranoia and/or suicidal rage.

It sounds like you need mental health intervention immediately.  Can you get it?  Find a hospital or therapist or a counselor to see you on an emergency basis?  That GP you saw was a waste of time, can you see another/someone else?

I would look for ways of getting out to do something that will help you get back feeling human and have some measure of self worth.  I suggest to some light volunteering but I would think in order to just function that you need to get some mental health help.  Churches or other places may offer volunteer counselors.  Just getting out of your house is a good first step.

Exercise and meditation are things you can do on your own without needing other people to assist as well.

Take care,
Mark