Doing a 3rd year is not the end of the world be it in AS or A2 year....i majorly fudged up my AS year originally, spent too much time at work, not enough revising among other things going on and as it was a fairly decent college they wanted minimum of D grades from three subjects before they let you continue onto A2. I got DEEU i was a little distraught to say the least as the college basically said you no longer have a place next year but my 100% attendence and my commitment to work harder got me back but then they had no restart places so had to carry on the D which was Eng Lit and they allowed me to continue to A2 maths on the condition that i resat the whole AS along side because i was 1 mark off a D but needed another subject as i needed 3 subjects for Nursing so i fought them to restart physics again which was the other E, fast forward to the next results i'd improved but had to stay for that final subject so did the A2 modules for Maths again (i really don't do that well in exams!!) continued physics and picked up an AS, Even with all this and only being predicted BCD i got an offer for Adult Nursing from Manchester University without an interview !!! I was shocked and pleased !!! I didn't end up going but i could have !!!! Now i have the job of my dreams and the third year has not adversely affected anything!!
Basically all i'm saying is if you are willing to work hard for what you want then you can get there !!