No, DROWN is a verb, so you can't be DROWN. If you want to use verbs that way, you have to use the ING form.
CORRECT
I was drowning.
I was eating dinner.
I was playing tennis.
INCORRECT
I was drown.
I was eat dinner.
I was play tennis.
So, your sentence should be something like:
I was drowning and my leg stuck out of the water. (adding SURFACE is unnatural)