Chemical?

My cycles vary anywhere from 29 to 31 days, they have ever since I had my son almost 3 years ago, but last month I began spotting on the 16th when I wasn't due for AF until the 20th-22nd. I spotted every day until the 26th and that is when I actually began bleeding heavy. I had zero signs of AF's arrival as I normally do (cramps and sore breasts). My period then lasted until the 3rd which isn't normal for me, I only have my period for 5 days.

I can't recall when I took the tests, but they were before my period was due. One came up with a faint positive then a few days later I got negatives. I'm going on the assumption that this was a chemical, but would a chemical screw me up this much? I always thought chemicals went unnoticed usually? Now here I am with light spotting again. I know I should get checked out, but I'm just wondering if anyone has an idea of what this is.

I spot nearly every month before my period. Since you got a faint positive, you may have had a chemical. It's hard to say. If you're concerned about the spotting, call your doc.