Spotting? Period?

Hi all. Sorry if tmi. But I'm out of people to ask about this. For the record, my normal periods are 5 or 6 days of moderate to heavy bleeding. So, back in january, I started bleeding 4 or 5 days early. I only bled for 3 days, and it was So light that I could hardly fill a tampon. But I just thought it must be stress or something. Well, february, I was a day late. But the same thing happened. 3 days of very very light bleeding. And both times, the blood was mostly dark, old looking blood. Moving on to this month, I have been nauseas and so tired. And (again, tmi I'm so sorry) i got a yeast infection. Which is very abnormal for me. Things just seem off. Has any one experienced this? What was It? Thanks so much.