Missed period but bfn is it perimenopause?? Sad

I had my first at 40 and my second at 42, but now I am trying at 47 like a crazy person. I know I was still ovulating at 46 and I am so upset I waited to get my kid out until last fall. I am very sad though, because we had sex like all through the correct days and I am very late for my period, and have never missed a period before, I have been right on target like 28-30 days. I took a test yesterday and it was bfn, so am I going into perimenopause??? I wasn’t on the levels yet but what is going on? I feel crampy but I am not nauseated at all and don’t have tender breasts. I am sad and upset I don’t understand.....