Spotting at 27 Weeks

I started spotting this morning. I had spotting all during my 1st trimester for no reason. Don't know why I am today. I cleaned the house then was on my feet all afternoon, but other than that, no heavy lifting or anything. Anyone else experiencing spotting this late? I hope it's nothing serious. I have a regular scheduled dr appt on Monday. Unless I'm in pain (which I'm not), I'll wait and tell the dr Monday morning. Just kinda nervous.