Strange period..I think?

So I am on the pill and I missed one pill three days ago. I have taken them regularly after that and have four left until I'm on my sugar pills. Yesterday I went to the bathroom and there was a little bit of brown discharge I guess, and sometimes that happens when I'm about the get my period so I thought maybe that was it. It went away yesterday but is back now, and it's not blood. I don't know what it is. I'm not supposed to start my period for a few days and they are always regular. Last night I had a really really bad pain in my abdomen as well and I had never felt anything like it before. I am also a really light sleeper and slept so heavy last night and woke up dizzy and woozy. I have no clue if all of these things are related, but does anyone have any insight on what it could be?