3 days before my period was due I experienced light spotting colouring was quite dark,which lasted for around 3 days.. a day later was my period due date but when it did come it was very much lighter and lasted 3 days with what can only be described as a half harted attempt period considering usually it comes thick and fast..
I did a pregnancy test a day after the bleed stopped but the test resulted in negative..
Any advice would be great please as even I am confused.
I do at the moment get a lot of headaches and the need to pee frequently.

We all get strange periods from time to time. The dark discharge is most likely "old blood" that comes before or after your period. Its not unusual to have a light period from time to time.

If you are still concerned, take another test in a week to be sure.