One day missed period and cramping

Here is my description. I have had a faithful period Every month. today I am a day late. I have been cramping all week knowing that it was coming but it has not came at all. Today I have been running to the bathroom because I thought I started that's how wet I felt but nothing was there except wetness. Took a test came back NEGATIVE, granted it was the cheap Walmart one... the 88 cents one. I am having cramps like I am about to start but nothing is there. Any advice would be really appreciative.I'm going nuts