Change to an OB?

I’ve been having pretty strong contractions since 20 weeks. I mentioned them to my midwife and she said only to worry if I get 4 in an hour. I wrote to her yesterday telling her my contractions were getting more frequent (3-4x’s a week) & I’ve been having a lot of vaginal pressure and soreness. I’m worried because with my 1st I didn’t get them until the end. I can’t do much activity this time around or my lower back hurts and contractions start. I’m frustrated because I feel like she’s not hearing me. She responded saying - only to worry if I have 4 in an hour and the pressure might be a yeast infection.... a yeast infection?! I have no symptoms. Should I switch to an ob I need to be heard.