I had one ovary removed over a year ago and have not had a period since. Last month I started spotting on and off and now I have started bleeding and period cramp like feeling. Is this something to be concerned about or normal?

I'd talk with your Gynecologist... even with one you should be having your period, and a regular one (assuming the remaining one is working normally). I assume you aren't above the age where menopause starts to occur for many women.