Help!!! Please help

Ar
I'm 22 weeks on mOnday, since last night around 11pm I've been having heavy mentrual cramps lower abdomen to pelvic bone and in the morning I went to emergency to see what was going on. But they checked baby and said she was fine but we're not able to tell me why I'm cramping non stop. I can't be mobile now so I don't know what to do. 
I've officially have been cramping for about a little over 12 hrs and I want this pain to go away...  I won't see my normal doc till Monday in the late day. 
This is my second child 
Anyone went through something like this or knows what's going on?????