My splits just suddenly stopped working, when I start my game the timer isn't running, any ideas how to fix?

What version of the game are you running? PC, N64? (And I assume you're referring to the autosplitter?)

I recently added support for another version of the game (the UK PC release) to the autosplitter which cheeseandcereal merged. I did test it on all the versions and it worked for me. I'll look into it as soon as I know which version you mean. Meanwhile maybe try going into your splits and redownloading the autosplitter as it could also be a LiveSplit issue.

im playing on n64, literally nothing has changed it just stopped working, also tried redownloading which didnt help at all

I think I know what the problem was. Try restarting and/or redownloading again. I believe it should work now.