Nuvaring Users, help please

Thila
So, I've been on the Nuvaring since October last year. And hadn't had a problem or serious or mild side effects.
I did have a early c section sept 2014
So I don't know if it's the cold messing with my muscles,
Or I ate something. But this has been a little bit
That I have abdominal cramping below the belly button and pelvic area. And just feel lethargic. And does feel a little bit like the beginning beginning of pregnancy, but not sure.
I do work a lot too. So stress?
But, for last month I had unprotected sex with my hubby the day before I was suppose to take it out and he did finish in me.(TMI)
Next day it was out, and I think we might've again during that week, I'm not entirely sure.
Can you get pregnant that way?
Or possible cause be pregnancy for how we did it?
Or just the cold cold weather or stress of working?
I have no one to talk to about this, and I know I should see a doctor but I'm working on my medical insurance renewal right now.