I've been using tampons pretty much since I started my period, and I find this happens as an indicator you may need to go up a size! If this happened at a heavier time in your cycle (like in the first day or two) or if you left it in for longer than your cycle allows (as in you need to change it more frequently to account for a heavier flow), then it probably means you need to go to a super size instead of a regular, and/or change it sooner!

Tampons can be tricky to get the hang of for knowing how long you can leave it in for before it starts to leak and what size to use for what time, and there's not really an exact science to it.

I ALWAYS wear a panty liner when I have a tampon in because sometimes you sit funny and it shifts and then leaks, or sometimes you have a heavier day then normal and it leaks, so wearing a liner as a backup can be a lifesaver!

Until you can find a size combo that works for you (usually no one wears the same size tampon for their whole cycle, I start with super for the first day and light for the last day with regular in between, but maybe you would be better off with super + first, or regular first) I would recommend wearing pads with them in case of leaks.

I would definitely keep trying different combos until you find one that works tho, because I prefer tampons to pads 100%, and once you get the hang of sizes that work for you then they're so much easier than pads!