Well, my boyfriend and I had sex on September 7 and 10. I had my last period the 1-3rd. Around the 13th I started getting cramps in my stomach and 2 days ago I noticed my breasts were sore and my lower back was in pain. I'm not supposed to start my period for another 12 days, but today my cramps got a little stronger, but not like my period and I started bleeding. It's like a red/brown. It sounds a little heavy to be implantation bleeding. It's very light, but has lasted all day. Should I wait a couple days and test or what?

My cycles are shorter than regular. 23 days instead of 28.