First off hon, well done for making the break because you knew the relationship was not good.
Now for the hard work but you can change and you must not be tempted to have him back just to assuage loneliness - a recipe for disaster as you well know!
You need to get out and about - you can make new friends and perhaps do some voluntary work during your daughter's school hours? There are loads of people in the same position as you and all it takes is a deep breath and a friendly smile and start chatting - what about the moms at the school gates ? do they look likely candidates for a coffee and chat? what about the school itself - do they have a parents association?
Is there any new hobby or skill you have always fancied trying - how feasible would it be to try something new out?
Do you have single parent groups in the USA - we have Gingerbread over here which is essentially a meeting point for similarly placed people.
I know it is really hard being alone (been there, done that and bought the t-shirt as they say!) but it really is much better than being in a toxic relationship which in the end makes you even lonelier than actually being alone.
You do actually sound a little depressed and perhaps a trip to the doc. to tell them how you feel might offer a solution to this or put you on the road to more positive thinking.