Angel care baby bath mold

So I’m crying right now because I feel like an awful mom, my baby has his own tub and we use the angel care baby bath because it has the holes and it’s milder resistant well today I flipped it over and there’s mold on the bottom and I didn’t even think to check there honestly because it dries and doesn’t sit in water or a closet I leave it in the tub to dry and then use it again. I don’t know how long it’s been there and I’m so scared I hurt my son in some way because he bathes in the water and idk of the mold gets in the water or what but I don’t even know, should I call and tell his pediatrician or am I over reacting? I just feel so stupid because I never looked because I assumed it wouldn’t happen being that there is holes and no closed spaces on the underneath and the big sticker that’s says mildew resistant😭