Hey AV
Never took celexa, but I do know alot of ADs mess with sleep.I always take meds first thing in the am just to be on safe side.
I have dreadful sleep too. Some suggestions that work for SOME- trazodone, hub takes amitriptyline, I take seroquel (BUT, it's a very potent anti-psychotic so not for most)...I take seroquel and 1mg Klonopin for restless legs. Some docs will prescribe something like klonopin but they are addictive and easy to build tolerance.
Ambien didn't do squat for me but works for others. I slept-ate on mine-lol.
Anyhoo, good luck, hope you find something
Love
Mags