Seeking advice on spotting

Hi,

Seeking some advice - I’m 18 w 6 days pregnant. At 17 weeks I started noticing some brown discharge. Dr. told me not to worry unless it became red blood. A few days later it became red blood. They did ultrasound and everything looked okay (no SCH, planeta looked fine, cervix was long/closed, and fibroids were same size). They told me it was likely an infection and to start monistat (test was inconclusive because of amount of blood). Bleeding got worse a few days later so went back to the doctor. Same result with ultrasound but this time Dr said not infection and likely just stress. Put on pelvic rest and no heavy lifting. Since then I’ve had consistent spotting and have been back to the doctor one more time- told me it was likely a yeast infection again and to take monistat again (didn’t test for it but did check my cervix and that was fine). I’m on monistat now but I’m worried about the fact that this is still going on. Spotting also seems to get worse when I walk around (even short distances). I’m at a loss about what to do. Any advice? This is my second pregnancy and I had no bleeding at all with my first. It has me very worried these last few weeks.