Is spotting blood on a daily basis normal?

i am 29 years old and i have 3 kids and since my last birth my periods became abnormal and then i started missing periods but i knew i wasnt pregnant because i had my tubes tide after the birth of my last baby so i don't think thats a possibility but i do miss my periods by months at a time and for the last month i have had spotting everyday but no period or if i lift something heavy or being really active i will have a gush of blood but nothing after that....i have also had 2 urinary infections within the last 2 months...i was just wanting to get some idea of what this could be so i could know what to expect from the ob when i make the appointment...is it possible to be pregnant or could it be more serious.