It's my last day of my period, and I REALLY want to go swimming!!!?

So, I'm only 11. Very sorry I'm underage. Anyways, it's my last day of my period, I think, because I only have a tiny spot of blood on my pad. (sorry..i know it's gross.) I already made plans to go night swimming with my friends. Yesterday, I tried to use tampons and I was just totally uncomfortable with them ... I probably put it in wrong. But I'm scared that it might be painful putting the tampon in and have only a tiny drop of blood go on it, then have to yank out the dry tampon. Ouch! So please .... any advice??