I bleed heavily for 2 days nd now i'm spotting what does that mean? usually my monthly lasts only 3-4 days

Just a variation: Not every period will be the same. It is "normal" for periods to occasionally be heavier, lighter, earlier or later. This can result from stress, illness, medications. Keep a diary for the next 2-3 months of any menstrual symptoms you have. If things go back to regular, no worries. If not, see a GYN.

Maybe normal: Always do a pregnancy test to exclude pregnancy. If you are not pregnant then this may be normal. It's not unusual to have an occasional variation from you usual menstrual pattern.