My experience with antidepressants (Prozac) is exactly like yours. Been on them for three periods over the course of about 15 years. First two times it worked and I came off them after about 3 months and stayed pretty good. This third time, it took a good 7-8 weeks for me to feel better - longer than the other times, and worse side effects in the beginning (which have now gone). I have read accounts of this same sequential pattern happening to other people. Just thought I would share that if it's helpful :-)
If you can do without sleeping pills good for you. Like you say, addictive.