Morning All

Apologies for not using the correct terminology but im not good with cars at all!
I drive a Vauxhall Corsa CDTI 2010 - When I started the engine this morning it showed the fuel at full - when infact I had already used a quarter - I thought at the time - fantastic - but as I put my foot down to over take the car jumped and the diagnostic light came on and now the car feels like it has hardly any power - it still goes up the gears and in 5th and 6th I still get to 70mph but feels like its gutless!!!

I know this sounds really vague but cant take it to a Vauxhall garage as they recently closed the two in my area - nearest one is 37 miles away and bit worried I could breakdown on route!!!

any advise or help would be grateful