No, not always. I had irregular periods for a long time and then within the past 2 years they have started to even out but then I would have a period one week, then it would stop then the next week it would come again. But don't rule out pregnancy, if it's possible -- you could be. Go to the doctor and get it checked out though. Or maybe even take an at home pregnancy test.
I had a very irregular period for a long time and bled between periods if doesn't mean pregnancy it means something is going on in your uterus
I just recently went through the same thing and I thought I was prego. I then thought it was a uti, I went to the dr and I had uti, and the general std tests done only to exclude some thoughts, they all came back neg. however the dr told me that my cervix looks prego. however when I tested 2 weeks later I was not and I got my period. I hope this helps you I know first hand about being in that situation.