What's going on with my body???

So I've had normal periods since I was 16 or 17. (I'm 20 now) Never been late nor have I had any problems. This past month tho I am a week late. The strange part that concerns me is that the day before expecting my period, I was cramping and experiencing all symptoms that it was coming. This lasted through today. But absolutely no discharge of any sort, not even a small amount of blood has been seen. This is going on day 8 and it's really worried me today because of how serious my symptoms have got.