Tampon Symptoms?

So, during my period my go-to product is a tampon. But during the last couple of cycles I've been getting really shaky when I have one in. Nothing super big or anything, just a little wobbly in the knees. This doesn't happen when I don't have one in though, so it can't just be the period, can it? Is that normal or do I need to be worried? UPDATE: As it turns out I was simply experiencing side-effects of dehydration (which is common with me, but is made worse by my period) and the tampons had nothing to do with it. Thank you guys for all your help and concern though!! :-)