Pregnant again and alone

So my story goes a little something like this my baby's father and I has been together for 2 in a half years we've gone through ups and downs but who doesn't well January 29th 2016 we welcomed a beautiful baby boy in to the world along with my oldest two from previous relationships and then in April I found out I was pregnant again and he was happy and so was I because our family was growing but I found out he was cheating and I left but we didn't break up we just needed space well 2 days ago he calls me and says it's officially over and he's not gonna be around for the kids so now iam all alone to raise my 4 by myself iam crushed and don't know what to do has anyone else been through this before all I do is cry