Minimise any contact you have with this man, in your shoes I would go to csa for maintainance thus cutting communication on that point.
Make sure that you have a court ordered contact if he has any dc with you, cutting communication and game playing on that possible issue.
Block him from contacting you untill he learns to have some manners towards you. Have a pay as you go phone just for communicating with him about dc, only using text or email (set up an acc just for this communication). Blocking him on all other avenues such as your usual email/phone etc.
Do not let him abuse you like this.
Seeking help from your gp may be useful, some councelling for instance. This will give you much needed support whilst you adjust to things.
About your pmt, there are practical things that you can do to make YOUR life easier, such as making sure that the few days you suffer from it are made easier by planning ahead and spending those days doing the minimum needed to keep things going (make sure that house chores are up to date etc). Let your dc know that you need those days to be quieter, calmer etc. I advise friends to be honest with their dc and say I am on my period and need some head space. Things like headphones and iPod help, quiet walks, lots of fresh veg and fruit, water, nice long baths. Some herb teas can help eg, scull cap, valerian, hops and passiflora. Raspberry leaf tea can help for the physical side and star flower oil for the hormonal drops that occurre. It really is worth your while to learn the effects of the different hormones, when they peak and fall during your cycle, this will give you a better understanding of your cycle and you can as I have suggested plan for the down days.
Have you any real life support?
And let your dc teachers etc know what is happening for them, they may need some support to.
Good luck and hope that you will feel better about things soon 