How do I get rid of bv... it keeps comeing back and I don't know what to do

Im 40 and just did IVF. HCG levels were going up nicely. Now week 4, the HCG only went from 195 to 300 in less than 72 hours. Is these numbers reason for concern? Im having ultrasound tomorrow but I'm preparing myself for the worst. Am I worried for nothing?