Surviving at a US startup

Peeps, just looking for some professional advice

I've been working for a US based series B startup from Bangalore for the last ten months. Given I worked at a FAANG type company before where things move slowly, I love the fast paced environment here and the kind of work I get to contribute. As a high energetic and motivated engineer, I'm able to create a real impact. One problem I face at this startup is, it has a hire & fire culture which always makes me feel unsettled.

I have been working 10 to 14 hours everyday being customer obsessed. Recently I leaked a bug to prod and missed to acknowledge an alert during my oncall (To give a little bit of context on my oncall, it's usually 10+ alerts a day). Due to that, my manager had a very hard conversation with me, where he mentioned if I repeat this, he would let me go.

I am a dedicated guy. I have delivered multiple features in the last ten months here in this startup. I have worked long hours and put in my efforts day in day out. Having to hear this from my manager was devastating for me

Please provide some advice, how should I handle this situation?