Is it normal to be having severe anxiety after giving birth?

Baby is 3.5 weeks old and I'm having a mixture of bad feelings;

- That something terrible is going to happen to him or his dad

- That me and his dad are going to split up and I'll be alone.

- That a huge terrorist attack or malicious political demonsrration is going to happen

- That we're gonna run out of money

I keep getting extremely stressed and panicky and crying to my fiancé.

I feel ugly and unattractive and even though he gives me absolutely no reason to believe it I'm really insecure and keep thinking he's going to cheat on me.

It's crazy!