Hey,
Sounds like a hip capsule issue.
But let's address the video first
1. Get a belt (almost Christmas ask your parents for one)
2. Don't give up tightness to get into the hole. There are a few reps that look like you're dive bombing into the hole. Try to imagine "pulling" yourself into the hole this should ensure you remain tight all the way down.
3. Abs tight will be a good cue to think of when your squating since you have no belt.
4. On the side view it looks like the bar floated forward of your mid foot a few times. Fix this by slightly lifting your head. Not much just a bit.
As for the hip capsule fix:
Try this video (skip to 2:50) Clearing Hip Impingement | Feat. Kelly Starrett | Ep. 87 | MobilityWOD - YouTube - try the first exercise only with the band. Do a test retest to see if you're noticing improvement. Spend about 5-15 minutes working on it daily away from your workout times.
There is a version of this exercise that doesn't require a band so you'll be able to work on this all day long inbetween school.
Let us know if that helps!
Ps. If you get some relief but not 100% better with the first exercise I have one more suggestion (but less is more so try the first one for a week and see how it goes)