Lightroom CC 2018 on Mac constantly not responding - help!

Please help - I am constantly having to reboot lightroom after it stops responding almost immediately after opening again and trying to start working. It has got worse over the last few days and I am extremely stressed as I have so many deadlines overdue for clients to deliver their wedding galleries and I've not been able to do any work.

I have tried updating the software, my mac, cleaned out/decluttered my hard drives, restarted the computer itself and it is still struggling.

I've read on other forums uninstalling and reinstalling lightroom might help - but I really don't want to have to do anything which might corrupt the catalogue and I get worried when changing or moving important files around. Would my catalogue still be in tact if I were to uninstall and then reinstall? (Sorry I am useless with this kind of thing) I'm not even able to back up my images or optimise the catalogue because I just get the colour wheel going round in circles so I just have to shut lightroom down..

Any suggestions or help would be much appreciated!