(Just my own honest, and worthless, opinions...)
This being your second ever go makes it hard to judge neutrally, because it's such an hard thing to do, nobody should have their 2nd, 3rd or even 4th, 5th, 6th sets publicly opinionated on.
Nice opening line/visual.
First min: bit light on jokes, which is fine, but your cadence remained as though you were delivering a punchline, which there wasn't.
2nd min: really picked up, the Cruise thing made me laugh.
3rd min: I lost the trail, the bit seemed to tail off into nothing cos the coded call thing lost me.
4th min: Loved the e-cig thing - with a bit of rearranging about it could be better. I reckon you could introduce the story with a better precursor (eg; "next time you think you're having a bad day spare a thought for the following guy..." or "before you think of quitting, listen to this.. etc" pref something less generic than those examples , break down the beats as you did, because, each line is a punchline.. the hospital bit made me laugh, it's funny cos it's true etc.
5th min: Try not draw attention if you blank - I used to - it's not good, your brain tailspins and every milisecond feels like an hour - but the crowd aren't aware, so, staying quiet is better, or even having a memorised default back up comment, anything.
6th min: Huston. the link between hitting the head and painkillers is v.funny, tighten it up though. The horror film bit was a fairly standard 'whats the deal?' sort of thing, lacking in point .
I thought your likeabilty carried you through, some of the stuff seemed a bit first draftish, I think it's obvious you're gonna get better and tighter because we all do. A couple of things are quite topical so unsure whether or not it's worth rewriting. The highlight was the story about the guy burning his house down, I reckon you've got good mileage to expand on that because it's somehing that actually does warrant that 'comedian' incredulity at the events.
All in all, fair play, an entertaining open spot.
The bottom line is; in ten or fifteen or so spots from now you'll look back on this and cringe because you'll be better, and so on. Don't judge yourself for a while. Just keep writing, all day every day.