Bummer, I know how it feels to crash a car
These days I like to think I'm always prepared for damp patches/horses/dogs/cats/hamsters, but if it was oil or something nasty on the road then you're screwed if you're leaning on the tyres even slightly. You don't have to be going fast to lose control...
Sounds like you were lucky to come out ok mate, and I echo the sentiments of others. You'll feel s**t about it for ages, but it will pass and you'll shrug your shoulders over it in a few months. The best you can take from this is some extra experience, and some gained wisdom that we should all expect the unexpected