I stopped taking the pill

[ash22]

I have been on LoOvral for 5 years I stopped taking it because it made me moody. Is it normal not to start your period when you should have had you still been on the pills. I want to start taking the pills again. Should I just start when I was supposed to or wait until the Sunday after I have had my period. Another question is it possible for me to be pregnant? I took several tests and they all were negative. I am only a few days late on my period. Could stopping the birth control effect the results of the pregnancy test?