Starting to wonder and need advice...

I have had a regular period for the past year or two. It comes like clock work and takes about 30 days-35days to come. It hasn't come since before Jan. 20th. Since then, I have gotten sick to the point of vomitting at least once and have felt tired. I took a pregnancy test sunday and it was negative but I think I may have taken it too early. My mother dreamt I was pregnant even though I have not told her about all of this and I now I have dreamt I was pregnant. My husband and I don't use any protection, we both decided a year ago just to "see what happens" and have sex around 3-4 times a week. Should I retest or is my missed period just me worrying now? Any advice on how to get it back? %-)