Question: If I am afraid that I have passed gas, does that invalidate my prayers? I'm always leaving salah and doing wudu because I fear I my prayer to be invalid.
Answer: Your wuduu' does not break unless you are sure that gas actually came out. If you are in prayer, you do not interrupt praying unless you actually hear yourself passing gas or smell it. This is because satan has the ability to make you feel as if you passed gas even if you did not.
You must never leave your prayer unless you are absolutely sure you passed gas, or broke your wuduu' for some other reason.
... and Allah knows best.