Hiya, earlier on, when I was 3-4 months pregnant I had a really bad pain behind my belly button. It was really sharp as if it was tearing open but apparently that is the baby growing behind it and the start of your belly button pushing out! I always had an 'inny' belly button, but now I am 5.5 months it sticks out like a sausage. Minging! Period like cramps are normal too.
Hope this is of some use.
PS when I had the pain in my belly button I thought that I was weird but it is very common xxx Good luck xx