I'm scared :( HCG levels? 🤷🏻‍♀️

According to glow I'm 4 weeks and 3 days.

This week I should have gotten my period. So far nothing which is amazing that's what we want. But I've been having brown (light brown) discharge and cramping. I've talked to the OB and at first she said keep on eye on it and drink more water. Then they called back saying the doctor wants me to go for my HCG levels. They came back 705. She said that was good so far and I need to go back to make sure they are going up. I'm starting to get really bad back cramps tonight, maybe nipples are sore and it starting to get really nervous. I just have to vent, look for advice or comfort I don't know something. I'm just scared and upset.