forgotten_aria

Just saw the google photos link. Does that say your run pace is around 10 min/mile, and maybe you started the first segment at slightly sub-10? Yes, I would totally not expect that you could sustain that.

Remember: 15 sec/mile is one quantum of running pace, so whereas I was guessing you should be at 14 or 15 min/mile, if you're starting at 10 min/mile, you are eight to ten quanta too fast.

To put that in perspective: you should be going at marathon pace during your run segments, and instead, you are going at slightly slower than mile pace. I'm... actually impressed that you could do a second segment and consistently hold that pace! Well done!!!

Now stop doing anything even vaguely like that for the love of all that is holy. :) Have a conversation with yourself during run segments that consists of 3-4 word sentences.
"How it going?"
"Not too bad."
"Too fast?"
"Nah, s'all good."
"You're a good runner!"
"Thanks, you too!"
"Not even hard."
"Yeah, kinda cool!"
"Right? Me too!"

1, being able to do that out-loud means you're not going too fast.
2, hey, free pep talk for yourself? Outstanding. :)