Help!!

Tia

I had a confirmed miscarriage during the early part of October and even had a negative test afterwards. But about a month later i started having similar symptoms and decided to test. Only thing is now My hcg levels are rising really slow. Last week they were only at 15, but I’m still testing positive. Having all the symptoms but my Dr still doesn’t know what’s going on. Has this happened to anyone else experienced this and went on to have a successful pregnancy/healthy baby?