Hi my names lynsey im 25 years old and really worried, so im hoping you guys can help!!!

I have my period around the same time each month which normaly lasts up to 6 days. after my last period with finished on the 4th....12 days later i noticed some brown/redish spotting (iv never had this before) so im not sure if its normall?? now im 5 days late on my period, have got a very very bloated belly, swollen breast feeling very tired in the day..literally so tired i have fullen asleep on my lunch break for the last 3 4 days and when i get home im in and out of tirednesss..i also have on off headaches which im not a suffer of headaches.im urinating frequently and pooping alot too. i have done two test which both have come back negative..so if im not pregnant and never had these sypmtoms whats wrong with me?

please help as im unsure if i am pregnant even though it was negative...should i take another test next week or is there somethibg wrong with my body.????

much appreciated

lynsey