Why while on your period? Because that's when you'll be using the cup. ;o)

Since yours is both high and low, two cups might suit you well. Or a medium length that might work for both.

My guess is that your vagina doesn't shorten all that much on your light spotty days -- it's just too dry in there for a tampon to slide around to get to its proper spot. That's why it's so uncomfortable and pokey. So start with a medium-to-long cup for your heavy days and then decide whether or not you'll need another for your light/spotty days. Whether cup or tampon, a dab of lube might help.

If you recently had the procedure, then it's not advisable as it takes quite a while for the cervix to heal and "grow back". If your cervix was removed within last 6 months, best to call the Dr to give you a clearance before using the cup.

I had part of my cervix removed as well via freezing method which they use this for cancer patients even though I don't have cancer. I had unexplained very heavy bleeding during sex that made it seemed like I was brutally raped and murdered (that messy!) I suspect that my cervix was turned inside out when the contraceptive was removed.

Doctor said the cervix would grow back like new and I went on to have another baby years later. Generally the cervix is higher during non menses period. It is also firmer.

I'm a very new user too and I have very heavy menses of about 150ml for the heaviest day alone. Most women have only about 50ml for the whole cycle. The cup is a life saver! I use the highest capacity one on heavier days and smaller cup for lighter days.