Running. Why is it so hard?!?

So i began no.3 of the life plan this week, aiming to get fit without either suffering a heart attack or failing to push myself at all.
Monday i put on the silly poor runner's clothes - White t-shirt, Jogging bottoms, faded-white running shoes, wooly hat, white earphones - and jogged home. It was okay, run for 1 minute, walk hunched over panting for dear life for 2 minutes, repeat the cycle until home. It took me 45 minutes (give or take some seconds) to get home monday, as opposed to a 1hr 10min walk, which i think is good. Well I do, because I felt like I was pushing myself whenever my heart had slowed, even sprinting down the last 200m street. Unfit, but taking my first steps, and not being a sissy about it.
Tuesday - my legs. oh goodness, my legs. My weak knees were okay, but my thighs and various other leg muscles were not able to fully relax at any time.
Luckily, Wednesday presented me with few obstacles in the way of torn tissue and disheartenment. I was looking forward to my 2nd jog home, despite the reports of hefty winds battering the south, knocking down trees here and there, when the majority of my route is right through Southampton Common. So lots of trees.
Trouble was, I had forgotten that i was going to meet my granddad for lunch today, as I had no guitar lesson this week (We meet Wednesday lunchtimes as he helps me pay for them because he's a good Granddad. A bit of a rude git, but I wouldn't have him any other way. I'll probably let fly some stories about him soon.)
So i wandered south along Shirley high street for some lunch, which i demolished due to no breakfast (BAD when you're going to nog on that particular day!) As soon as i bin the rubbish, Gramps texts me:
"You comin' to subway Bruv?" (we talk like Chavs on the phone because he works for a local secondary school driving minibuses and we mock the kids all the time).
So I peg it down to subway, thinking 'I'm going to have such a stitch when I'm going home tonight' all the way. I did only have a 6-inch sub when i got there, but it was still too much.
He informs me he has a new girlfriend, probably the 5th this year, who "doesn't beat around the bush", whatever that means. Actually, I'm not sure I want to know. He's nearly 70 but acts like he's 21.

So after work, I adorned the humiliating gear of the ammeter jogger once again, and proceeded to walk up Shirley high street with some Dream Theatre in my ears to get me psyched for it, doing some stretches when i turned off the main street, and proceeding to move in a more brisk pace.
Surely enough, when i got to st. James' park (300yrds), I have a stitch. Or two. Ouch.
'Just turn up the music, Ellie' I tell myself, 'Pay no attention to the people giving you funny looks because of the sound of your rapid, deep breathing...'
Stiches all the way home, and it feels like i've run less than i did last time (45mins to get home 1st time).

But when i arrive home, i find i've done it in 30mins.
WTF BODY?!?!
You're stuffed with food, cold, stiff from previous run, and you improve by 15 minutes?
By that logic, i'll be home in a quarter of an hour on friday (which i doubt)!
Anyway, i suppose it's all progress.
Ooh, and Asthma hasn't showed up yet, so that's good!

Thanks for reading!
Elliot