Afraid to work out during TWW

Callie
I'm so afraid to run and do other things. I've changed my work outs to 20 minutes running and 20 minutes of chair step ups. 
But I'm on cycle day 20 and while doing step ups I felt pinches on my right side. I was so afraid I stopped.
I don't want to gain weight because I want to maintain a healthy weight for me and baby. 
I can't test for another week but I'm so afraid. What should I do???