Advise eh: Well for starters you were askin for trouble goin on your maiden trip through the city, and also, crankin it before you get your brain used to anticoast, duh mate you're lucky you've still got skin on your shnoz!!! But hey it's good to see you got back in one piece.
It takes some time to get used to. Go for a few smaller rides with less traffic around, maybe jus go to your local big carpark and fuck around for a few hours. Practice stop starts. Practice some small sprints to quick slow to teach your brain that "Hey if I give it this much gas, it's goin to take longer to slow down and I still have to keep that RPM up till I do". Practice slow speed turns using whatever's around i.e the painted lines, cars, peds dogs...?
What gear ratio are you using anyway?
Maybe next time you ride fixed somewhere, give yourself another 5-10mins to get there and ride a lil slower, thus enabling yourself to delve further into the fixie ethos.
Have fun.
Idesa
P.s. I aint no vet