Why are you going back onto a diet that you clearly can't sustain? What makes you believe you won't, in time, gain back the weight you are losing now?

Crash diets work for a few people, sure: people who have the self-control and determination to adjust to a normal diet following the crash period. But the vast majority of people they simply do not work. I'd have given you the benefit of the doubt before, but your past experience clearly puts you in the latter category. So why continue?