misdiagnosed miscarriage?

Hello! I neee advice. At 3w5d I had a blood test to confirm pregnancy. My hcG levels were 3,000. At 4w1d I had repeat blood work and my doctor told me I had miscarried due to the fact that my levels dropped to 300. She offered me a pill to speed up the process but I opted to wait for nature to take its course. I had no miscarriage symptoms, no cramping, spotting, or bleeding. A few weeks passed and I began feeling nauseous, vomitting, and heartburn. I called the dr and the nurse told me I probably had a stomach bug. With still no signs of miscarriage I insisted on more blood work. Later that day the nurse called And said my hcG levels were back up to over 30,000! Has anyone else had levels significantly drop and then raise?! I'm so confused and don't want to get overly excited since just 2 weeks ago I was mourning. Help!