Pill confusion // sorry for the long post!!!

Destiny
Hey ladies 💁🏽
So I seem to be spotting this month. Yesterday my period came but it was really light (I usually have super heavy periods and my cramps would be so unbearable where I'd stay in bed and sleep it off. Sometimes I'd end up fainting or throwing up from it. The pill has lightened it up a bit though) and I had slight cramps. Then the next morning, all I got was light pink discharge that seemed watery, then stopped. And I've been getting that since. My period always only lasts 3 days. 
I'm thinking that it could be because I've taken my pill too late down the track (as in not on the right days) because I got a bit muddled up with it this month. 
Could that be the cause? Is that even a thing? I'm trying to cross out every other solution before I even think about pregnancy 😂