Should I take a pregnancy test

So I was supposed to get my period on Saturday, May 7th and I still have not gotten it. I had a miscarriage last June and a chemical pregnancy in September. My husband and I have been trying ever since then and no luck. I took a pregnancy test on wensday last week and it came back negative. My period has been out of wack. Some months it's on time and others it's late. Should I wait another week before taking a pregnancy test? Help. Has anyone else experienced what I have gone through?