My last two periods were VERY late and VERY light?

I don't know what's going on, I was worried I was pregnant because my last period was a month and a half late and when it came, it came for a day because I wiped and saw pink, so I put a tampon in. It stopped coming and I thought that maybe I put one in too early and messed up the flow (no pun intended). It didn't come back so I was concerned that I wouldn't know if I stopped it or it was spotting. Based on the time I was late, though, people were saying that implantation bleeding occurs way before that. My cousin even told me her doctor said spotting is likely to occur in the 3rd trimester, more likely than implantation bleeding (and by then, I think you know you're pregnant). I have very little reason to believe I'm pregnant because while the pull-out method (only used twice) is not effective, and you will lecture me on the effectiveness (save it), it's not until the last second; my boyfriend has never remotely been close to missing the mark, if you know what I'm saying. Anyway, my period has been late consistently this year and one time it was so late (the firs time it was a month and a half late) I spent money for 6 tests 6 different for them to say negative! So last time I didn't test and I didn't have ANY systems. No sore breasts, sickness, excessive hunger, cramping of any sort - nothing. So this month, it was the same amount of time late, and I was just over it. I didn't test again, and I got my period from wiping pink, but it's been SO light. I just want to clarify, my period is heavy. I have never been lucky to have a light one, and while I hope this is a new thing that is welcome, I'm not sure of the longevity of it and what it means. Could I still/have ever been pregnant? It's lasting about the duration of a normal period...it's about reddish pink, it varies. I've even not been wearing a tampon or anything at all because it's so light it doesn't make it to my underwear even but comes out enough to be there when I wipe a few times. So far, it's lasted 4 days which is why I'm thinking it can't be spotting. It's coming out consistently, just that light though. Thoughts? Oh, and still no symptoms of anything at this point. I'm just pretty moody which is normal, and even my breasts don't hurt.