I did it! Thankyou to everyone who gave me advice and encouragement about moving on to Week 2 I don't think I'd have been ready after only three Week 1 sessions, but after 5 sessions I decided to give it a go, and it went well!
I went swimming last night (first time back in the pool in several years), so I expected to be thoroughly knackered this morning, but it was fine. It was actually fun (never expected to write that!), if tiring and very hard work. I surprised myself by being able to do the 90 second runs, and I'm looking forward to my next one.
Did help that the weather was stunning this morning, although it's clouding over now
My arms ache a bit from swimming, but my legs still don't ache, although they're tired and running up the stairs is definitely far more of an effort now than it was before the run!
Need to head out for a walk later. I might even make my target of 4 miles walking today if I'm lucky!