The sun was shining, the steel drums were playing - but by the time I crossed the line at The Big Half, I was burnt out, broken and questioning my life choices
A record 17,193 people took part, running through the streets of London - past Canary Wharf, over Tower Bridge and finishing at the Cutty Sark.
It was a brilliant event on a bright and beautiful day.
I'd stayed on a mate's sofa and was up early to catch a bus into central London.
I squeezed into a window seat and watched the landmarks go by, including the Olympic Stadium, where so many legends were made in 2012.
Soon, the glass towers of Liverpool Street loomed ahead.
I jumped off at Bank as the sun was rising - a giant fireball creating views that would surely have even taken William Wordsworth's breath away.
I walked down to Tooley Street, where hundreds of other runners were following the signs to their "wave".
There were portable loos galore - at the bag drop, at the start line and en route too.
Everything was clearly signposted, including after the race, where we were handed water, Lucozade and a protein smoothie before collecting our medals and running tops.
Organising such a massive event in one of the world's busiest cities, on the brink of a tube strike, cannot be easy. Yet it all ran smoothly.
"Know thyself..."
As Socrates said: "To know thyself is the beginning of wisdom."
In other words, don't kid yourself.
But it's hard to think rationally when you're surrounded by thousands of runners at a start line.
The music is pumping, people are jostling for position. You get caught up in the buzz.
I got chatting to another runner who, like me, was aiming for 1 hour and 26 minutes.
The adrenaline got me. Plus I had my super shoes on. Somehow, I thought I could go that fast for 13.1 miles.
But even the race announcer was warning people that the sweltering conditions were not ideal for a PB attempt.
I started at my goal pace (4-minute kilometres) but soon realised something wasn't right. At 170bpm, my heart rate was too high to maintain for 90 minutes.
It got even worse when we dipped into the Limehouse Link Tunnel, which quickly turned into a concrete sauna.
I managed to hold out until the eight-mile mark, when I knew I had to slow down if I was going to make it to the end.
I wanted to stop so, so badly.
I'd like to be able to tell you how amazing I felt as I crossed Tower Bridge. But by then I was so deep in the pain cave that I could barely see the sights.
While other runners were keeping to the fastest line, I was heading straight for the showers spraying water across the road like mini oases.
Looking at the event photographer's pictures, everyone around me is smiling and waving. I'm not waving, I'm drowning.
Lessons learned
I crossed the line in just over one hour and 30 minutes - a time I would have been delighted with 12 months ago.
But it was about five minutes slower than I'd hoped.
It's the first time things haven't really gone to plan for me in a race. But maybe that's a good thing.
I've learnt a lot.
1. Don't go out too hot. It's a horrible feeling to be overtaken by hundreds of runners towards the end of a race.
2. Be ready to adapt. If the temperature's too high, adjust your goal pace so you don't burn out.
3. Forget Strava. Enjoy the experience, find your groove - and don't worry about the kudos.
4. Know your limits. In training, work out how long you can maintain a high heart rate or fast pace for. Don't expect miracles on the day.
5. Keep positive. Racing is hard - but it should be fun. Remember how far you've come to get here.
Never again?
Every runner has had that thought mid-race: "I'm never doing this again."
I certainly did on Sunday. I questioned my life choices. Why am I doing this to myself? Is it worth putting in all those hours of running every week?
The answer must be yes because I've signed up for another half-marathon at the end of the month - and then the full 26.2 miles back in London in April.
Double the pain and suffering?
Months of early mornings, running in the dark and the cold?