Hi, Irregular bleeding, heavy bleeding and spotting can be seen as side effects of the hormone treatment. Yet, it is always advisable to exclude/confirm pregnancy, though the possibilities are rare. You should get a serum beta-hCG titre estimation since urine pregnancy tests may not be of use in your case. Please see a specialist, get a complete evaluation along with a trans-vaginal sonogram, blood counts and urinalysis. Please maintain a healthy weight and genital hygiene. Hope you find this information useful. Take care.