Week 5 is done! I was nervous but followed the advice and focused on the excitement of running for 20minutes... it worked. When Laura said I was only in the first 5 minutes, I worried as I assumed I'de be minute 10 and I was already getting tired... I obvs went too fast (too excited!) but focused on slowing down and breathing and then after the 10minutes I regained control and was really enjoying it. It was a happy run, out of breath of course, but happy.
And TBH even after enjoying this, I'm happy to go back to the run+walk+run in week 6! Thanks to all for the advice.