I just turned 50 the other day so I still identify with ''in their forties'' 
If I could go back to myself at 36 I'd say,
There is a difference between a confident introvert and an extrovert who lacks a strong healthy self esteem. You're the latter.
Work on your self-esteem. Read/listen to Nathanial Branden's ''The Six Pillars of Self esteem'' and do the exercises and go back to it. It's for everybody, not just for people who have zero self-esteem.
Hypnosis can help with anxiety so give it a go.
Don't bother doing ANYTHING just be conform. Getting married, having a baby. Blah blah blah.
I think there is probably maximum pressure on women in the run up to 40 to ''make it right'' by meeting somebody and having a baby. And then that passes and you stop feeling the pressure and you think, there were / are so many ways I can find happiness and fulfillment and now I can't because I'm a single mother and trapped with 100% of the responsibility.
Now, staring down the barrel of my 50s, I don't feel that people are pitying me for being single! I used to worry about being pitied 
Seems strange to fathom it now.
Don't bother your arse with a new relationship unless it's EASY and makes you happy. If you have to work too hard at it, then you're doing all the work I bet.
Finally, 36 is still very young. If you want to change careers or get braces or train to be a zoo keeper, you can still do it. The time will pass anyway.