Bathtub tumble

Sooo I was giving my baby boy a bath. We keep a laundry basket in the bath with him so he doesn't slip. Well he decided to pull up for the first time, he stood there for a second just fine and leaned over and went over the basket and under the water. Of course I was right there and scooped him up, but of course being me I googled and now dry drowning or delayed drowning is in my head! He cried for just a few seconds because he bumped his head on the way down, but continued to play and crawl around. Now its nap time and I'm paranoid about him being sleepy as that's one of the symptoms!!!! Someone tell me this happens all the time and there's nothing to worry about!!!!