Should I see a doctor??

So I do have an irregular period. My cycle can range from 28 days to 34 (was the longest). My period was supposed to start on the 10th... I waited a bit just incase, took a test on the 14th & on the 17th. Both negative. Now it is the 19th and still no period. Maybe I'm just not going to have one this month? I doubt I'm having a 41+ day cycle... Do I just try again next month & how do I know when I am ovulating this time? Or does no period mean I didn't ovulate this last time??