Trouble Waking Up

I wake up pretty early (7am-ish) but recently I’ve been turning my alarm off and then falling back asleep and not waking up until much later. Thank goodness that I’m on vacation or else I’d probably be fired at this point. How can I break this habit? I’m a heavy sleeper and the reason I keep my alarm clock so close by is because I’m afraid I would be able to hear it when it goes off.