HELP ASAP?!

Can your period be late? Can ovulation never happen because of it? I have no many questions HELPPPP my period is suppose to come in a day and all I have is been pooping a lot and tiny cramps rn ( I took a plan b though and it ruined my cycle ) so idk I took a test dpo 10-11 days and it was negative. My period is suppose to come tmmrw but I’m not sure I don’t feel any pms