I can honestly say I know how you feel,its no Fun to spend $$$ on a Race-Car and not have any Fun with it much less not make any $$$ with it,I have "Been There Done That"!
But I just refuse to fail at something I want to do and will not give up.Because it does get better sooner or later more the later.
And once you get back on track again it will then be like you can do no wrong.Then once I got back to I could do no wrong I was doing good but it was more like work than fun.Now its fun again and I am more happy than I ever have been with my Racing,and believe me it is now worth all the $$$ and hard work.And I believe in the end it will be for you as well.
My best advice to you is if you are burnt out,step back get you a fast Street-Car I can not tell you how much Fun they are after you grow up and no longer a Teenager,but never even think about selling your Race-Car for the next couple of years.In a few years if/when you change your mind about Racing you will only have to refresh everything and maybe do a few up-grades and that will be much cheaper than having to buy everything.
PS Once you get Racing in your blood you will never be able to walk away from it! Good Luck