Ya let the pressure get to ya.
You are still afraid of the audience. The idea is not to care if they laugh they laugh, remember ya goto provoke a laugh by making them think.
Throw away the teacher's comic books they sold you and try not to rehearse the jokes or your lines. Just remember the core parts of a joke line, ad lib shit in.
Your stuff is funny though it really is.
My friends when I was working my way up with the guitar always said Mark its not your playing, your playing is fine, but you are afraid of the audience, you dont look confident. The only way to break this in an audience situation is not to care.
Thats the hardest part
Don;t give a shit if they laugh or not and do not wait for them to laugh, if they do fine they don't let it hurt your confidence. If ya hit a bad note fuck it, rip into the bad note and move on
Ya got talent though and I am not telling ya that cuz you are "Steve Lightspeed" I am tellin ya this because ya got potential to comedy man I seen tons of Comedians live from Chris Rock to Dana Carvy to Jim Carry