When I was teaching the classes (basic & advanced), I used only the front brake for a long time so I could get a feel for the mass transfer as I slowed and increase pressure as the weight/mass shifted to the front of the bike.
The most common way you can crash using the front brake is to squeeze it hard and then let off of it, then you high side because of the direction changes...
Glad you're ok OP, practice makes perfect
There's 2 kinds of riders, those that have crashed and those that are yet to crash