threatened miscarriage

Had some moderate bleeding today and the ER diagnosed "threatened miscarriage" and the ultrasound put me back to 6 weeks when we thought I was 8 weeks. But the heartbeat was 120 and everything looked good. I do have a cyst on my right ovary, but she didn't seem concerned about that though. She said 50/50 chance I'll keep the babe. Anyone else been diagnosed with this? How'd it work out for you? 
I've already had 2 100% healthy and 0% complication pregnancies and vaginal deliveries. Never experienced a miscarriage. But it's been 7 years and I'm quite a bit heavier than I was then. 
I guess I feel like this should be easy and should be able to do this without complications. I guess that's ignorant to think since every pregnancy is different. 
Thoughts, advice, experiences, please share.