Spotting while wearing a tampon

I’m just starting to use tampons, and I noticed that I get a little bit of spotting on my underwear when I use them. I’m 100% sure that it was in correctly because I couldn’t feel it. I think maybe my flow was a bit heavy, but when I took the tampon out it wasn’t even completely full and my underwear were pretty stained. Any suggestions on not staining underwear while wearing a tampon? (I don’t really want to wear a tampon and pad at the same time)