Negative Money

I was playing with money mod on singleplayer because I dont want to use it on online, after I was playing for a while on solo I realized I got 2.1 Billion after racing for a while then when I buy an item or a car my money turns negative. Right now my money is -20,703 and when I try to sell a car that is higher than 20k it says sell failed and when I try to do a race that gives 40k I didnt get 40k after the race I was also 1st I tried restarting my game without mods nothing changed it is still negative but when I do something lower thank 20k it lessens but I'm still stuck on negative money.