After fitting a new fuel filter this afternoon in an attempt to cure my own 'hesitation' problem (unsuccessful, but the filter was shite anyways), I was heading back from the gas station and accelerating fairly enthusiastically in second
when, at between five and six thousand rpm, ALL the warning lights on the dash came on and stayed on. The engine sounded fine, so I went home (at a reduced pace 
).When I parked, I let her idle for a minute, but it was REALLY high, like 1,600rpm high. Then the lights went out and the revs gradually sank...to less than 500rpm! I switched off, waited, restarted, and the revs were still a bit low but not as bad. (Checking under the bonnet revealed the filter and hoses to be sound, so hopefully that's irrelevant.)
Can anybody diagnose me?
Should I be worried?