iPhone alarm won't make sound

I keep on waking up so late and having to miss days off school because my alarm will go off but won't make any sound and then I would eventually wake up by myself when I should've been in school 2 hours before and my alarm is just on the screen but not making sound and so obviously it didn't wake me up.

This is very annoying as I really hate having to take a day off school because not being up in time. For example my school starts at 8:30 and so I planned to get up at 5:00 to wash my hair and get makeup done and that so I would have plenty of time to get ready but as it turns out, my alarm decided not to make sound and so I ended up waking up at 8:20 so I cannot wash my hair and do makeup which would take 2 hours and then walk to school because I would get there at 10:30 which is halfway through the day and this has happened more than once and it is extremely frustrating.

I just want to know how to make it work.