Irregular Menstrual Cycle and Painful Cramps

Not really sure if this is something I should post here, but it's something that's bothering me the last few months. Most women have their monthly approximately every 28 days. For the last 3 or 4 months, I've noticed mine have been every 24 days, which in itself isn't too alarming. Then, this month, I started only 20 days since my last cycle. I've also noticed that my cramps, which I really never had a problem with in the past, is now not only present, but painful enough that there are days I can't get out of bed hardly because of the pain. One last thing I must note, because it feels like it's important to mention, is that I am coming up on my one year clean date from my drug of choice, which I am hesitant to name here. Is this something I should be concerned about, or is it normal for my circumstances? I'd ask a doctor, but I do not have th ability to see one at this time.