Bye bye confidence!

I need some help & advice, please! Ever since having my first baby 3 months ago, I've been insecure. I can't go to the gym due to my husbands work schedule and the fact we live far from family and friends. I hate this added on muffin top I've accumulated from pregnancy and I typically don't care for myself sometimes.
I get jealous of my friend. She's so pretty and everyone likes her. She's incredibly like able and everything I'm not. I wish I was more like her and less insecure like me.
Even at the grocery store I can't look people in the eye or say "excuse me" without mumbling. 
Any help would be appreciated. I want my confidence back!