Possible Preterm labor?

I’m freaking out right now but I have anxiety so maybe I’m just overreacting. I’ve been having period like cramping and back pain yesterday and today. I just started timing them in case it’s contractions but I’m only 28 weeks pregnant. I have had pelvic pressure the last three days that’s made it hard to even put on pants by myself because it hurts to lift my legs. I’m getting vaginal discharge that’s just clear and watery which is unusual for me because I’m usually very dry. I’m also a little nauseous and my heart rate is high. Not sure what to do I’m afraid if I call my doctor they’ll just think I’m crazy.