Period being weirld lately

My period normally last 6/7 days

And was always on time or maybe 1 or 2 days later that what the app says.

For the last 2 months my period have been only for 4 days.

And today I woke up and when I wiped with tissue, a light pink "mucus look a like" tuing came out of my vagi.

And my period is not due for a whole 5 days.

I have been nauseous for the couple of days.

And had light cramping in my lower abdomen.

And also had a little pain in lower back.