Im using an apple laptop and i saved my project then clicked exit now trying to open the project back up it opens but the editing that i did isn't there and most of the videos arent there and another issue I tried to export it before I clicked exit and the export screen i couldn't see the full screen
Premiere Elements is reliable software. From your brief description, I suspect you are making some procedural mistakes.
You provided so little information so I'll start with a first guess. The video clip assets have been moved or are on a drive, card or device that is not plugged in.
If you want more help, please describe the details of what computer you are using, what version of the software you have and where the clips are coming from. Then try to detail your procedures. Screen shots help a lot.