6 Week Heart Rate

I had my ultrasound at 6 weeks and heart rate of baby was measuring 174. Dr says it’s very strong but I feel that’s quite high for being so early and with my history of miscarriages I’m so nervous and not feeling confident. I’m often cramping with random, bad sharp/shooting paints in random weird spots in the pelvic/vaginal region, along with random bleeding here and there sometimes brown, pink and even red. I go back in early tomorrow for a check/ultrasound to see how things are and I’ll be 8w1d.

Has anyone had anything similar? I feel being such a strong heartbeat it’s a great sign, but I also worry it could be too high, if that’s a thing? My levels double for the first few blood draws but the last two they didn’t fully double.. close but went from 918 to 1257 in two days. Still rising but this was similar to my last two miscarriages.

I guess I’m just a bit nervous things will continue to not turn out positively and maybe just needed to post/vent to get it off my chest! Probably won’t be sleeping tonight thinking about the possibilities of tomorrows ultrasound lol!