From what I understand, sick leave for a miscarriage is a bit of a grey area. Legally, it doesn't have to be counted as pregnancy-related sick leave. Saying that, it would be pretty hard for a company/organisation to stand up in court and argue otherwise so most work places count it as pregnancy-related. It is important to find out what your work place's policy is.
If you are offered a meeting with occupational health, it is probably best to take it. They are on your side (who in their right mind will argue with time off from a miscarriage!?). If you refuse, it looks like you are not cooperating with work and it will make your situation look worse.
Iluvbump, if your boss is spreading rumours that you refused an occupational health meeting you need to put the record straight. Instead of getting into a confrontational situation during a meeting with both your boss and HR, maybe you could have a private meeting with HR beforehand and go through your concerns?
It's all rather horrible and I've currently got a grievance open with my employer, too. Since last year
Still, my HR and occupational health have been very supportive.
Good luck with everything!