why dont you start training in rounds on the bag?
this only has benefits in my opinion.

and if you can throw punches as hard and fast as you can non stop for 10 min, with just a lil movment around,
man you fit enough to last in amateur A class competition. (dunno about your skill though)

you should start training in 2 min rounds to get the feel for the round.
cuz you start in amateur doing 2 min.
but do some more rounds just like alex said.

good luck