As Trophywench shows, it's important not just to state a sympton eg heavy periods, but also to state how it affects you eg blood leaking on bed, carpets, clothes etc. Admittedly even if they do listen, they can't always solve the problem.
I'm in a similar situation, where saying that I can't move my knee since falling down a cattle grid isn't considired very urgent by the NHS triage system, although GP has suggested what I say to surgeon (when I eventually see them) what have already said to orthopaedic specialist GP about limits on activities such as walking (have to do work patrols by tractor instead of on foot), running, kayaking, orienteering (work and leisure) etc.