Two years ago, I also went on one pretty exhausting ride, that lasted 2 weeks. During that time I had my period but I haven't had any problems. I used my tampons and everything was o.k.
But this year I went on one MTB racing event and after that I bled a little bit even though it wasn't my period, and my gynecologist said that it may be due to various reasons but one of them is my overexertion. So either way you must be aware of your possibilities and don't pressure your body on something just because it is for a good cause.
I wish you all the best