Newly diagnosed at 52 and struggling

Hello

I'm a 52 year old woman and recently diagnosed as autistic.  I feel so sad and angry and am struggling.  I've always known I was wrong and very different but just plodded along, tried to fit in.  

I've had depression, anxiety and OCD since I was 19 but with no real relief from medication. If medicine doesn't work what does?  I'm mourning the life I could have had if I'd had support all those years ago. I know times were different but I'm drowning in questions. Would I have stayed in my career longer, could I have saved my marriage, would my relationship with my 3 daughters be better, 2 of which are autistic?  The list is endless. 

Does the anger pass?  My GP has been brilliant but I'm cross with him. I've had numerous chats with him over the years.  Why didn't he pick up on it?  

What difference will the diagnosis make?  I feel too old for it to matter anymore.  My mind feels scrambled and if I'm honest I'm scared for the future. How do I know if my symptoms are due to depression, anxiety, autism, ocd or the menopause?

I just feel very alone.

Thank you