When you say you could smell something burnt, do you mean electrical burnt or bunny-caught-in-exhaust-manifold burnt?
It will be a surprise if it IS the starter, not because I don't suspect it - because it is possible - but because the starter motor should not have been operating while the vehicle was moving.
It's possibly the fuel pump that's burnt itself out. If that's producing a dead short (or close to it) it will draw a huge current, drop the battery voltage and cause the starter to run slow - but the pump will get bloody hot while doing it. Crank it over and if the fuel pump is hot after 20 seconds of cranking, shut her down and pray you can get one through Nizzbits.