I've been on nexplanon for almost 2 years i've always had irregular periods this month i haven't gotten it yet no symptoms of pregnancy could i be?

Unlikely: Nexplanon is the most effective method of reversible contraception, because once it is placed, it works without any effort on patient's part until removed. If you are very anxious/concerned you can get and perform a urine pregnancy test from dollar store to reassure you. More likely you missed period due to stress, illness, excessive exercise or weight change. Take Care!