What do you think?

Okay...so basically, I have irregular periods. They're always on a different date every month, so I never know when I am ovulating.
​But it has now been 5 and a half weeks since my last period, and I am having very strange feelings. Headaches, bloating, nausea, sore breasts, backache, thighs are aching, constantly tired, and some cramping, but still no period.
​I did a test today, and it was negative. Does anybody think that maybe it was a false negative, or do you think it could be right? Should I wait and do another test if my period doesn't come soon, or should I just let it go and accept the fact that I am probably not pregnant?
​Help! Don't know what to do, or what is going on :[
​Xoxox