Don't know if I'm pregnant or not

So my period is now a week late, but I've been cramping and have had sore breasts the whole time. It's been almost a month since the last time I had intercourse and I took a test a week ago just to be safe, but it came out negative. I know that should tell me something, but I also know that sometimes those tests can be taken too early. I've never been this late before and now my cramps are actually starting to go away, and still no period. My boyfriend and I aren't really trying to have a baby right now, but we aren't really taking any precautions either... Should I try a different test or maybe wait a little longer before testing? I'm trying not to stress but I just feel like my body is off somehow.....