I really need advice

I am 7 weeks pregnant now and have had some issues. I had a miscarriage last year, followed by a d&c. This pregnancy has been going well, but week ago I had some spotting. I went to my Dr early, and saw my baby with a heart rate of 140. He said he found no reason for the bleeding, other than that some women just bleed during pregnancy. The spotting subsided and i felt ok. Well fast forward to Friday night i started spotting again, and by Saturday morning i was concerned enough to go to the ER. They took my blood & ordered an ultrasound. The baby is doing well with a heart rate of 152. The Dr said he saw no cause for bleeding on the ultrasound & my blood work and urine looked good. He simply called it "first trimester bleeding". My back has been hurting some, and every time I wipe I see a little red. It kinda subsides at night, but returns. Has anyone else had unexplained bleeding like this? It has totally freaked me out. All I know to do is pray about it. Pray without ceasing. Just wondering if anyone else has gone through some similar. Thank you all!