Does having a period make me feel awful sometimes? Sure. But we've all got used to just having to get shit done regardless. The burden (exhaustion, pain) falls on us as women, not the companies and organisations we work for, because of all the women I know, we still get it all done regardless.
Some men are incredibly stoic about pain, too. But others collapse at the slightest thing - there's a reason "man flu" is a standing joke. (Can you imagine how most men would cope with having blood flow out of the tips of their penis as a regular occurrence? Can you imagine the fuss some of them would make, and how heroic the narratives about menses would be?!)
And as for hormones - men have them too, just different ones. I look forward to a thread from a man about how being a slave to testosterone had made them make some bloody stupid decisions, got them into needless conflict, and had adverse affects both on their own careers and the companies they work for.
Women do take more sick leave than men, on average - but it isn't to deal with their own illnesses, the discrepancy is down to them taking the days off to care for sick children. If more fathers pulled their bloody weight, then this discrepancy would disappear.
I don't think our periods affect our careers at all - it;s patriarchy that does.