Stressed out!

Melissa • Have 2 beautiful boys, pregnant with #3 after 3 miscarriages
I am almost 5 weeks and have been having really bad cramping but only at night. I went to the gym today (made sure I didn't do anything strenuous) and now I am in so much pain I feel like my stomach is going to explode. I have had 3 miscarriages so I'm really stressed that something is wrong. Is this normal? I would really appreciate some advice :(