Citalopram

Hello everybody.I have been on antidepressants since the end of June 2013.I started out with Citalopram (celexa) and it was doing a good job but my sex life was almost nil (delayed orgasm).The doc than had me try Wellbutrin and it kept me from sleeping and then i tried Cipralex and it did absolutely nothing .I then asked my Doctor to go back to Citalopram .I found that withdrawing from these meds was almost hell on earth .I started back on Citalopram at the end of September and all was well until this last week.Is it normal that after almost four good months that you feel as if you are going back to the starting line? Could it be that my dose is too strong( 20mg) or not strong enough? I take my medication at the noon meal and it took a bit of trial and error to find the most effective time of day.I also take Crestor (10mg) and Dexilant (60mg) everyday. Thank you for your comments