Spotting at 10 weeks

I’m 10 1/2 weeks pregnant and on Tuesday my husband and I had sex. Wednesday I noticed some light pink on the toilet paper after I wiped. I went to doc and US showed baby moving with a heartbeat of 176. I was told to go home and rest and see what happens. Thursday morning early, I got up to go to the bathroom and wiped and it was bright red. I put a pad on and waited until the doc office opened to call. I only had a small area of dark blood in my pad for the whole day. They had me come back in and did another US. Baby was still moving with a heart rate of 166. The tech measured my cervix and said it wasn’t shortening which was a good thing. She also said she didn’t see the placenta yet. I asked if that was a bad thing and she said no bc it usually forms between 10-12 weeks. She said she had no answers on while I was bleeding and I just needed to play the waiting game. They put me on 48 bed rest and I’ve been having very small brown spotting when I wipe and every now and then a spot in my pad but no bright red blood since that one time. Has anyone had this happen to them and had a good outcome? I’m pretty nervous as I had no bleeding in my first pregnancy.