What worked last time. And what caused you to slip up and regain do you think?
What were you doing last time? Has this all happened just recently?
Anyway to restart is something of a mystery but one idea that i think is worth trying is focus more on eating better food and less on restricting for a little while. With you success at eating better food at about maintenance calories, you may find it will shift your mood to be able to make the transition back to reducing easier.
In your focus on good foods, avoid eating a lot of carbs, especially sweet foods and junk foods. Focus on including a lot of fresh fruit and vegetables, enough protein, some good fats such as can be found in nuts, and seeds but if you are meeting eating, then limit them. The reason i recommend eating so widely is that with all the extra nutrients and fewer sugars it should help to rebalance all your hormones and thus your appetite.
This time round i've read up a lot about the part hormones play in weight gain and loss. You can read up on it on nutrition wonderland too.
Once your appetite settles down you can start reducing your intake of total calories. You can count or not. doesn't matter the scales will show the difference but don't try to starve yourself. I always eat something when i start to get hungry but i try to avoid boredom eating by changing activities. I minimise stress eating by eating fruit and vegies and other healthy things, i.e. just sticking to my diet rules.
An alternative kick started might be to do a one day water fast. There are other fasts that might work but don't do it for longer than two days. And if you are doing it for two days, you will need some calories., preferably not from fruit juice which is high in sugar and could cause insulin spikes.
The french women don't get fat book talks about a leek soup fast. Its a nice book, worth reading when you are learning how to find a healthy way to eat for the rest of your life. I just read it.