Paxil Restart - please help

I am 3 weeks back on Paxil after a failed attempt to switch medications to Lexapro.  I have read a lot that Paxil loses its effectiveness after the first time.  I (stupidly) have started, stopped & restarted Paxil on several different occasions and it always has seemed to work.  I was on paxil 20mg originally then stopped cold turkey and went back on at Paxil CR 12.5.  Upped dose over time to Paxil CR 25mg.  Recently that didn't work so I tried switching to Lexapro to try out a different drug (which didn't work) so I am back to paxil.  Started Paxil CR 12.5 3 weeks ago and have increased each week by 12.5 to where I am currently at now on Paxil CR 37.5.  Should the dose increase work?  Has anybody had success with this?  My psych stated that I have to be on the medication for a month or more to start feeling the full effects.  If I just started 37.5 last week, does that mean I should expect to see something in 4 to 5 more weeks?  Just looking for some answers.  I'm frustrated and with the medicine change I felt like it just set myself back.  Been feeling bad for almost 3 months now.