Well give yourself the credit in knowing that you messed up, and realizing that a mistake was made. You should look into mental health care centers in your area, they usually work on a sliding scale of your income. And in the future maybe see if you can get a larger quantity on your scripts.
It seems as though your ex and you aren't on the same page with things and because of that it may make you stronger to be able to get on your feet without him.
As you have said you have been through many challenges but you have made it through them, I understand that it wasn't easy and you are probably still not where you want to be but you have made it past the bottom. Look at yourself in the mirror and give yourself the pep talk you need. Recall all the crap and see that you have come further than where you were before and forward is still possible.
I will hope the best for you.