Two things I learned (very recently, I’m no expert) about running:

1) Recovery is my friend. In endurance training, most of the time I should feel relaxed and be able to converse in normal sentences…not gasping out each word. I’m not good at pacing, either. I bought a running watch just keep me from pushing too hard but it still happens. When I push too hard, I slow down until I’m recovered and continue on.

That may seem obvious but makes more sense when I add…

2) Walking is not stopping! If I need to walk to recover, that’s just fine. It took me a long time to change my own mindset that walking was not allowed. If you keep moving forward, you have not quit!

In fact, walking is integral to some run training plans. Tim Williams did his first marathon by running 8 minutes and walking 1. And, if I remember right, he finished with an amazing 8 min/mile average pace.
Lots, probably most, of non-professional Ironman triathletes walk during the marathon portion…some a little, some a lot. But they keep moving forward. By reports, one Annapolis Tri Club member walked almost all of the marathon at Ironman Lake Placid last week. But that was part of his plan….and he finished!

Anyway, keep responding to pressure the way you are now, and you won’t have anything to worry about.

Just have fun.

If it makes you feel better, I’ve had to wuss out of running on multiple occasions because I pushed myself too hard and gave myself “carpel tunnel of the foot!”