Don't put yourself down for falling for a loser. Bear in mind many men will have done the same thing also and had the indignity of being 'dumped'.
Trouble is we do not KNOW what people are like until we know them for a few years. You may be lucky and live in a small community in which you can always find out about a suitor. In the modern age this is not happening so much and people often move in after a whirlwind romance.
Obviously right now you need help in a few things other than romance which should be way down the list for the next few months till you get sorted out.
His pets - you can maybe get them to some shelter. I'd have left them at his home but maybe your not like that.
Get any of those cats neutered if you can. You do not want more.
You need some education course or other, after you get some help with the issues you have. The loser who left you, had he been a man, might have helped from the start with those. I wonder if he dumped problems on you as if you were a free counselling service for assholes?
Also, maybe leave Facebook alone for a while. I don't use Facebook, never set up a profile because maybe the past is best left to chance encounters and not some bloody search function!
I mean it about the education courses, or maybe voluntary work which can be done without affecting any benefits you may get. This might help you in your anxiety and give you a goal that makes you feel better about yourself.
Very best of luck to you. I'm sure you can use this opportunity to cope with the anxiety and deal with the practical issues also.
Have you no family you can talk to?
If not share your feeling here as were all brothers and sisters in a sense at least. A stranger would jump in a lake to rescue another stranger. Most of the time they would. We have a connection towards others and empathy.
Hope you find a nice man one day and I'm sure there are plenty of eligible men in your part of the world. Concentrate on yourself for a while - the few practical things you have to deal with are a mountain to climb when lumped together, but its like a sink full of dirty dishes - one by one, bit by bit - think of it as a series of single problems not some mountain five times the size of Everest and covered in slippery moss, ice and oil.
Have a Spring clean also - clear up the evidence of Mr Loser.
Nothing worse than a man who has not got the courage and decency to tell a women he does not love her any-more. It is cowardice.
Good luck!