spotting a little at 27 weeks

Me and my husband had sex after like a week and a half. It felt really uncomfortable and painful. 2 days later I had a little bit of spotting in my underwear. I had extreme stomach and back pain, but it went away. My legs are also killing me, feel like I'm going to fall if I stand a second longer. Have I pushed my self to hard? What can this mean? Can you guys please give me good advise. I am calling my doctor tomorrow.