Worried For Slightly Enlarged Uterus With Slightly Thickened Uterine Endometrium

For the past 3 months I've been having heavy periods, spotting in betwen, cramping pelvic pain, and lower back pain. My last period was 4/26/11 lasted four Days and then spotted basically every Day after. I'm very worry now because I'm bleeding heavy for the past two Days and the pelvic U/S shows "Slightly enlarged uterus with slightly thickened uterine endometrium" My GYN is out of the office until Tuesday, Should I worry?