Hair loss in 4.5yr old

[Mumofoneandanotherontheway]

Hi, I needed some advice pls.
My 4.5yr old needed a hair cut and I gave him one at home (to best I could do). Noticed since then when he rubs his head a few stands of hair falls out. Yesterday DH brushes his hair with a baby hair brush (one of those tomme tippee ones) and I saw today there was a lot of his hair in there. He hasn’t got patches of hair loss or anything. Should I be worried?
He’s had 2 hair washes since his hair cut, I doubt it could be hair left in his head.

Please advice I’m getting really worried. Otherwise he’s a healthy little boy x