Download a circadian rhythm app/ sleep cycle app, you go through phases of sleep about every hour and a half going from rem sleep to deep sleep. Waking up during deep sleep is incredibly jarring, it is when your body is furthest from awake and you will be guaranteed to feel groggy waking up during peak rem sleep is relatively painless because as far as your brain is concerned your not far from conscious. Theses apps should ensure that you are being woken up at the right time to feel energetic even if it could be a half an hour before you need to get up. They will also usually have a gradual alarm that gets louder the longer you leave it so it is only as loud as needed to wake you and isn't waking the whole house