2000 civic P0135 code

Howdy, Boy I could sure use some help. I have a 2000 honda civic that the service engine light came on. Since there was a sale on ODB-2 readers I thought I would take a shot at figuring this out myself. Read the code P0135 o2 sensor bank 1 heater. So I replaced the o2 sensor upstream of the cat. converter. Prior to replacing it, the car would run okay , but did not accelerate as well as prior to the service eng light. Also when you came to a stop after moderate speed (35-45 mph) engine would idle rough and almost, if not die. When I read the code, the reader had the EV and C feilds still flashing. After replacement of the o2 sensor. Car accelerates nicely, but still develops a rough idle. What should I check next? Are these flashing feilds indicative of something? I suspect I may have a bad PCV valve, or is my converter on its way south?

Thanks for the help I am kinda lost at this point.

You convertor is cracked where the O2 sensor screws into it .Major problem with these .I've changed hundreds of them .It will cause many driveabilty problems.Hope this helps