Help toddler hit head

i’m waiting for a callback from my sonsdoctor. I mopped earlier today and I had put the chairs on top of the dining table and right now as I was putting them back down from the dining table my 17 month old son grabbed and pulled one and it fell directly on his head. I feel like the worst mom in the world. he cried immediately and when I picked him up he was crying a bit but no longer than two minutes total. Whenever he cries hard like that he gets sleepy so I am mediately got up with him and we went outside and he’s been running around with his puppy laughing and babbling like normal. he doesn’t have a bump on his head or anything nor any redness but I’m still so paranoid. any advice please. His doctors is closed but The secretary told me he would call me back soon. I’m about to take him to a pediatric night clinic right now to double check. Has anyone’s toddlers hit their head in a similar way and been okay? He’s still laughing and smiling meanwhile I’m 7 months pregnant and a complete wreck worrying.