About to confidently have a quicky, hard to flat for no reason

So my partner got me excited unintentionally. I have been with Mojo for a few weeks with new found confidence. So I go to the bedroom hard, she pops to the bathroom for a minute. In that minute my heartrate spikes and it goes flat before she’s back. I tried breathing slower but there was no time. She was no longer interested.

I’m gutted because now not only is my confidence ruined again but her confidence that this is working, it fell into an argument pretty quick. The unanswerable question (I thought you were getting better).

My question would be, is there a quick way to nip that sudden panic in the bud? Is there a way to maintain the confidence?