PLEASE HELP ME!! Lexapro worked incredibly well, BUT ONLY FOR ONE MONTH!!

I´ve been fighting depression for about 4 years now but I hadn´t been medicated. I tried exercising and other natural stuff, but I seemed to just get worse and worse. My husband was a cheater and an abuser and I was in very bad shape. However, even though I was still in this marriage, Lexapro worked great. Finally (after 27 years of marriage), 10 months ago I left my husband. 14 months ago I started going to a new doctor who prescribed me with Lexapro. After a couple of weeks it started to do wonders: I ALWAYS (really, ALWAYS) have a headache, day and night, and its very bad. I had been using nose drops (Afrin) for years....... maybe 20 years about twice a day!! After about 2 or 3 weeks of Lexapro, I suddenly found my nose drops and realized I hadn´t needed them (and hadn´t used them) for at least a week!! I very often have a heartburn. This also stopped completely after a couple of weeks on Lexapro. I was feeling great! Optimistic, strong, etc. I never knew I could actually simply "feel fine"!! I mean, without a headache (this is what´s most disturbing because they were so bad and ALWAYS there). Unfortunately this only lasted a few weeks... maybe a little over a month, and then, I gradually got all the sympthoms back. My doctor increased the dosage, gave me Lexapro combined with other antidepressants, etc, etc, etc, This has been going on for a year already, but NOTHING has worked. I would really like to feel ok again but I guess I just never will. I´ve taken Cymbalta, Wellbutrin, Effexor ...... nothing has worked. The ONLY THING worked for me was Lexapro......... but ony for a very short time. Is there any hope? Is there anything I should ask my doctor? Maybe if I take very high dosages of Lexapro? If anyone can, PLEASE HELP ME.