I do feel for you, Starting. Your situation is particularly hard because of not, at least at present, having a group of people in real life whom you can call on just to give you a hug, and hold you when you need to sob your heart out. You must desperately wish your Mum and Dad were still here to comfort you and look after you.
If it were me in your position, whilst I'd be glad of the support and advice I'd received on here, a little part of me would be wailing, "Yes, but it's all right for you lot! You've all got loads of people to look after you and I haven't!"
I wish I could give you a hug - and that's coming from someone who's been accused of being physically unaffectionate by her eldest sister (she's lucky I haven't yet smacked her in the gob, tbh - she upsets everybody!). And I've got another sister who gives the worst advice in the world. I've found it's best do the direct opposite of what she suggests, and things might then have a chance of turning out ok! So RL support isn't always all it's cracked up to be.
I do wish your EX would take his mobile and shove it up his arse. But since he's not going to, the onus is on you to ignore his missives, both (seemingly) nice and nasty. I really would take the advice of the posters above to change your number or block him - you have absolutely nothing to gain by responding to him. He's stuck a knife deep in your heart, and you're letting him prod at your open wound.
I hope you will have a calmer period now after all the emotional turmoil of the weekend. As a number of posters who've been through similar have said, it's a rollercoaster - you'll have to expect these ups and downs, but eventually you'll be gliding along with equanimity, hard though it seems to imagine at the moment.
xx