The last line gave me pause and catapulted me in to the reply box when I had no intention of being here. But now that I'm here I'm going to give you my 0.02.
It is OK to regret the mistakes you've made.
There are plenty of awful things you did over the last year. Some were done with malice and some had more innocent intentions. Either way, I wouldn't accept "I'm happy where I am now" or "I've learned a lot since then" as a valid reason to not have regrets. Saying that you have no regrets shows a lack of awareness about how your actions have affected others and, in your case, borders on tasteless. You don't regret hurting her? You don't regret burning bridges with your past employer?
The reason that I write this is that I want to encourage you to not settle for aphorisms in place of real reflection about how you really feel about the last year. Your regrets shape your future. It's important to pay them their due.