Anyone have a previous premature baby?

This is my 4th pregnancy...3 boys. First 2 full term and last one my water broke at 22 weeks 1 day and I had him at 23 weeks 3 days. He is now 3 and doing great but it was a long road to get here. I started bleeding early on with him and now that I'm pregnant again I'm worried about every little thing. I stopped working out hard...just walk and run. This morning I had some pink discharge and some cramping throughout the day...then nothing again until an hour ago...pink discharge again. This is a red flag to me because of my last pregnancy...but it could also be nothing. My nurse just told me to monitor everything and take it easy.