Can say anything without saying erm/um, if I try it's a severe block 90% of the time

Can say anything without saying erm/um, if I try it's a severe block 90% of the time I (M20) have had a stutter since i was like 7 and was wondering if you all have any advice on how I could fix this a bit. I always have to say erm and if I don't, I literally can't get a sylable out. Would really appreciate advice