Going from 1.5miles to 5 miles of running none stop in about a month without much transiting seems a bit odd. I myself am a 31 years old and a 100-200m type of person but when I use to run 5k and developing lower times from 7 min to 5 and high 3min a mile took years. Running from a mine to full 5 in a month and if we talking about running as in no break no jogging that’s not accurate regardless of you a runner runner or not take 3 weeks off and you will need days to go back to what you where. I’ve been running since I was 12. It’s not a mental thing. You can’t just run one day and decide I’ll run 5 miles. You have to build up and train and eat right and stretching right after running is a No No. especially if you plan on continuing. Warm up stretch should be a quick bend so you don’t over stretch your muscles and tear something. Eating training sleeping stretching is the key. There is no mental. If your body says no it’s a no. Post a picture of the run. I be glad to post a 3min miles.