hahaaaaaahhhhhhhhhhaaaaaaaaaaaaaaaahhhhhhhhhhhaaaaaaa.
ok. got that out of my system.
Yes. Replace it. Without it, your Alternator will not turn, which means your battery will not recharge; which means very soon you will either a. stop moving as your plugs/ecu no longer are getting a electrical charge to operate or b. you won't be able to start it.
A belt is cheap and it takes about 5 minutes to fix. From your question, lets assume you do not know much about cars. Pay someone 5 -10 bucks or a friend some beer to do it for you.