Oh Maggie, sorry you had a bad night. Back off on some of the big hip stretches until it calms down. When you are in the water and want to try to float, try this. Lay on your back, let your knees bend so your feet are pointed down but the rest of your legs are on top, then stretch your arms behind you letting them float on top of the water behind your head. Many people have trouble floating the conventional way because of the difference in their center of gravity verses their center of bouyancy. Men in particular but also women like me have to do it this way. I even have to point my fingers up towards the ceiling to get the right effect. Play around with this next time and take it easy on the hip. Moderation is the key.
Have fun
Cindy