Glitches (APP)

I recently uploaded 400 clips to a project and started editing the video. Of course it was a bit slow, but it still worked. I took a break and set my phone aside, once I tried opening the app on my phone it doesnt open and shuts down.
I already purchased more GB, cleared my memory, and turned off and on my phone but it seems like nothing has worked.
I heard if you reinstall you lose footage or any projects so Im scared to do that.

jimmyneutron321 about iMovie, v2.2.3