Blood

Hi all i finished my period a week ago and have had random spotting since I also have a slight pain when I pee im assuming the beginning of a urine infection again so im drinking lost of water now but im not sure what the blood is if my husband ripped me it kinda felt like he did a few nights ago that maybe I just have a tare I only notice when I wipe sometimes if I wear a thong some is there to. Any ideas I also started the depo shot on the 20th of Oct so im not sure if this is just common with it..