Implantation vs bleeding tmi info

Thought I was gonna start my period but only got spotting for 3 days. My periods are irregular but never that light. 
       The color was dark, then red red, light pink and clear. 
       Took a test, both negative. 
        Also, I think I'm getting a uti or something because my vagina is slightly itchy but there is no discharge or smell. 
    Been eating lots of yogurt and cranberry juice, any advice would help!