Seriously mate- I would try and resit and get a Tutor. I got BBC first time round for my AS maths modules [not the overall grade which was B, just the modules] and I needed an A to get into uni, so with the resits and the modules I did in second year.
I felt dumb getting a tutor at first when none of my mates had it, but I came out with a modular score of AABAAB which equalled a decent A in maths overall. I only got my tutor in february of this year and I took 5 Maths exams this summer in june, it really helped. You learn more one on one in an hour long session than you learn in a week at college I know that for sure.
I probably could of got better A levels than I did and got free monies at university, but you live and learn. I started working at the very last minute when i had a bad exam at the end of May which acted as a wake-up call, but it was too little too late for my other 2 subjects and I ended up just missing out on the grades necessary for Bursaries. If you don't want to do A-levels, then get yourself some vocational qualifications but re-sit the core GCSE's, you really do need some sort of academic qualifications on your CV.
If you try to revise and find yourself doing anything to avoid it- this happened to me- then remove the distraction- uninstall all your games, delete all your save backups and set yourself time limits for going on the PC, watching TV etc because all these steal time which you can never get back in your life.
Hope the advice people are giving helps, some of it is sound and I think some might say Mr. Smith is being harsh but sometimes that's what it takes to make you realise you've been kidding yourself.
Best of luck whatever you decide.