Lexapro VS Celexa, any difference? Experiences please

Started 40 mg celexa, felt like crap, lost 10 lbs, headaches, but began to feel better during 2nd week (less anxiety, obsessing, depression, DR). Figured i'd switch to lexapro, to get same effect, and perhaps less side-effects (10mg). Now im back to where i was.
Don't know if to go back to celexa, or up the lexapro to 20. I know they are virtually the same drug, minus one isomer (2 molecules).

I'd appreciate advice and experiences.