38 week membrane sweep

I go in for my 38 week apt tomorrow and my dr said he would do a full sweep. Last week at my apt I was 1cm and 50% effaced. I've been experiencing a lot of lower back pain and cramping and yesterday for two hours I had bad contractions 6 min apart that lasted a minute each but then stopped. Anyone have any luck with their sweeps working?! I'm ready to meet my little boy! 💙