I had an open appendectomy 5 months ago, i started going to the gym again. did enough time past so i can lift again?

In general yes: Glad to hear you are recovering! it is ok to resume lifting at this point, but it could take up to a year for your abdominal wall to heal up to full strength. In general i recommend my patients ease into strength training after abdominal surgery, since core stabilizers may be weakened. I also recommend refraining from maximal lifts (1rm), and to keep squats and dls in the 5+ rep range for a year.