Was wondering weather you could help, I have missed a period and am 5 days late on the next, I have done 4 home tests, the doctor done 1 urine test and have also had a blood test and all have come back negative.

What could be the problem, could there still be a possibility of being pregnant or should I rule that out completely.

I have had brownish discharge, slight cramping to the left last week, gained weight and have felt dizzy a few times.

I am not under any stress, not excercising excesivly, and have not lost weight, when the doctor done the blood test he also tested for thyroid and that was normal and there was not an increase in my hormone level

Please could someone help!!

Possible a pregnancy didn't get picked up earlier, but it is unusual. Maybe this one is still going to show up. Give it several more days then you might ask your doctor about another blood test... this one being a quantitative test that will give you an actual level of the hcg hormone instead of just a positive or negative result.
Could be your cycles are off and he will do some more hormone checking.

Usually doctors can pick up on pregnancy very early with blood tests. Take another just in case but I doubt your pregnant, exspecially since you got the blood test pretty later on. Mind of matter could be a case.
Ask your OBGYN when you see them and they will probably be able to narrow it down. It could just be a missed period. We all get it.
Hope this helps!