How much blood loss is too much during pregnancy? Do you think I should be concerned?

I'm curious. I had a few very faint positives before my period was due. Af was originally due today. Yesterday afternoon while at work I had started minor bleeding mainly a darker red but some fresh too it continued into this morning it seems to have stopped for right now, but I also have had mild/moderate cramping since this started. But it was enough to almost completely fill a pantiliner. Should I be concerned? Could sex could've caused this? I had sex Thursday night and my cervix is soft, high, and closed. Once I get my period my cervix is alwayd low and very open. I am still experiencing mild cramping even though I don't seem to be bleeding anymore. I'm concerned and scared. I have the weekend off so I was gonna be on bedrest just to make sure everything's okay.