Pregnant or NOT pregnant 😭

Eden
Hi girls! 
So I am 2 days late on my period which NEVER happens I have a regular 28 day cycle.. day 30 now! 
I'm having slight cramping which I'm not sure if is my period coming or what! 
I took a clear blue electronic pregnancy test today and it came up with error! It said Not pregnant but underneath it said 2-3 3+ 
Has this ever happened to anyone else? 
What does this mean! 
Really don't know what to think right now and I am half excited and half waiting for my period to arrive! 
Thanks in advance xoxo