My cycle is extremely prolonged on the iud this month. could i be pregnant?

Unlikely. If you had sex since your last period and missed your period by more than 4-5 days, do a home pregnancy test. If the result is negative repeat the test in 4-5 days, unless you get a period by then. Menstrual irregularities are not uncommon and anovulatory cycle is a common cause. If you miss more than two periods it would be time to see your doctor.