Help please.

M.
Okay, so my period was due on Oct. 1st, it ended up not showing up for four days. Which is odd since it's always on time. All tests I took came out negative as well. On the fifth day I got it, it was normal red and whatnot a good amount but not as much as normal. It lasted four days with 2 days of spotting. Now, today I just went to the bathroom and when I wiped, I noticed a extremely light pink discharge on the toilet paper. Does anyone have any idea what this could be? I've never had this before. Thanks in advance!