HELP pro cc not working at all when I go over 10 clips

I would like to state that I am quite new to editing

 I'm making an edit of 1080p 24fps Xbox Game DVR footage, I've done the same with 720p DVR footage no issues same with 720p mp4 files, I used about 30 clips in the project window for both, there were no issues. However, with this project, whenever I add another object of any type, image, video or otherwise, it COMPLETELY BREAKS. it's utterly unusable, and I mean COMPLETELY unusable, I cannot touch anything apart from the top tab options. I have 12 items on the project right now, a sequence, an MP3 file, and 10 of the game DVR clips, when I add a 13th item, it will start to breakdown until I delete said 13th item and it works like roses again. It's super weird. And whenever I start a new project it does the same. I'm getting extremely desperate here as the only solution I've found is I can export whenever I reach the clip limit and build the edit piece by piece like that, but that obviously severely hinders my ability to make it good and I really, REALLY want to be able to push this edit to the limit without having to do something so obtuse. HELP PLZ