I Just Finish My Cycle. This One Was Like Many

I just finish my cycle. This one was like many I've had in the past. I will go a few months where everything is fine I am like clockwork. Then at odd times I go a month without a cycle. Then the next month I have between a week and two weeks of spotting and finally then have bleeding. It's heavy for five to seven days then turns to spotting. What is going on?