I Have Never Done This In My Life And I'm

I have never done this in my life and I'm almost 39 yrs. old. I left a tampon in me for at least 3-5 days. I have no clue how I did not notice. I had light bleeding and I really thought I took it out and didn't fully start my period. I've had mild cramping yesterday (which we away) and figured I was going to start. I feel fine, but freaked out. Should I visit a doctor today?