Am I miscarrying?

So last month, on 2/4/15 I found out I was miscarrying at 6 weeks. I found out recently I'm pregnant again, drs measured the baby to be 6 weeks on ultrasound last monday. Yesterday I woke up to pinkish spotting and it was very speratic. Throughout the day sometimes it would get kinda heavy and it came out pinkish red. It only happened once though. And I had no more spotting yesterday. This morning I had some brownish spotting so far. I talked to my dr and forgot to mention the spotting. She told me from my blood work friday and Monday my hormone levels went up but didn't quite double, and I have to do more bloodwork today after work. I've also been having lower back pain like something is up with my kidney. Idk, help!