The only way to know for sure is to see a doctor who may be able to see something (like an open cervix) during an exam or do lab work (which may detect low hCG levels--the levels of the pregnancy hormone).
Of course, since you are experiencing an early period, there's a good chance you aren't pregnant but are having a different period. If you're new to th pill, this could also be breakthrough bleeding.

In terms of cramps and back pain: sometimes, a change in diet (such as an increase in caffeine and/or red meat or a decrease in calcium) can cause women to have worse cramps and pain.

In my experience with my 5w+ miscarriage, I did have bad cramps. They were like contractions in labor. I have severe menstrual cramps, but these cramps were obviously different.

Sorry I couldn't give you a definite answer, but I hope the information helps. Call your doctor, if you're able (and if only for peace of mind). Good luck. I'll be thinking of you :-)

I know exactly what you mean. Last August I started bleeding about a week before my period was due. I was bleeding quite healily and had terrible back pains the day before. I suspected for a couple of days before that I was pregnant so I knew in my heart that I had a m/c. I have done some reserch after that day and found out that many women have miscarriages so early that they mistake it for a normal period. Talk to your doctor about any concerns and listen to your body.

See your Dr.

I don't want to scare you sweetie but I got pregnant and miscarried while on the pill. If this doesn't seem normal to you I would see your dr.

If I did have a miscarriage, am I going to miss future periods or is it not going to affect my body because it was so early?

after my miscarriage i had a period about a month later...it didn't take long to have a "normal" cycle again, but I don't know if that's typical. I would say within a month or two you should be regular...but it also depends on your b/c - that can mess up your cycle whether you are new to it, or have been on it awhile. any concerns though, definitely see your doctor, it could be as simple as a vitamin imbalance. ( i recently had an iron problem that caused strange bleeding, and it was thought to be caused by my b/c)