DMCman - I strongly encourage you follow your dreams and apply again. You will always be wondering "what if" otherwise.
I've been doing the job for 6yrs now after having a previous professional occupation and it seriously is the best thing I have ever done. I have amazing managers in the centre and my colleagues make every single day an absolute joy, not to mention the job is so satisfying and rewarding. Yes the hours can be tough, but a lot of my friends have great working hours yet can't stand their jobs/bosses. So it's a small trade off.
You get out of the training what you put in. ATTITUDE is huge! Put in extra hours after class each day, have study sessions on weekends with colleagues, go to the instructors and ask if one would be happy to stay back an hour after the shift to go over some things. So many trainees used to blame all their struggles on everyone else other than themselves and ATC is all about taking ownership for your own mistakes and being able to immediately put your hand up when you're at fault (or not!!).
Go for it. It's so worth it.