My XH left me 8 days after my DSS were born after a Caesarian. My parents lived abroad and I lost a lot of friends during my pregnancy as friendships were built around going out etc. One night it got so bad I called an ambulance because one of the babies was crying and I couldn't get out of bed to reach him (at that point my sister came to stay, but we have a tough relationship)
I worked in a night shift job too so all my colleagues weren't around when I needed to call them as they'd be at work. I had no money either other than savings (not much) meant for a holiday after the babies (the irony).
It was tough. I had to go and actively seek help. I did what felt like the soul destroying thing and came on mumsnet and asked for help. I've now got 3 very close friends and also joined a support group through my GP.
I have really tough days. My XH left me for someone 8 years younger and she's now pregnant. He doesn't see the DSs much unless he's trying to impress her.
What I'm saying is... it gets easier; you get tougher. I promise!