Yesm you are using AP if you don't have H1 visa stamp.

But after return, as long as you still work for the same employer and your H1 status (not visa stamp) is still valid, you can continue your work. You don't have to use EAD to continue your current job. In your case, since you used EAD already, you are no longer H1 status. You won't be able to extend your H1 status. If something wrong with your I-485, you will be out of status.