could someone help me to fix the back end problem?

[Andy Chongsatitwatan]

irst of all i need to tell you the problem. the problem was i was using prestashop 1.7.3 for a year without any problem. then from last friday my back office stated to have some problem when i click anything at the back end it will go back to log in page though i can't do anythin then the next day everything on the back end was gone the column and everything gone only have textx left i'd tried to fix it but desperately can't do anything at all until today i decided to uninstall prestashop from the server and reinstall the new version but when i get in to the back end i still got the same problem everytime when i try to click something to set up the website it kept going back to the log in page. what do i need to do? feel so desperate with prestashop. my website have a lot customer come in everyday but now i have to start to do my website all over again but seem to be impossible because i can't really do anything. Should i give up on prestashop and using other platform?