My BBT chart but BFN at 8DPO

Im currently 8 DPO. I feel so tired since 5 DPO...always sleep early..my boobs hurt at the sides and had cramp below my belly..at 7 DPO i felt dizzy and nauseaus...

Today 8DPO my BBT rise...sneezing and have back pain...slight nausea...so i

take the test, BFN...so i dont want to get my hopes high looking at my bbt chart, i really dont know much how to interpret except when i ovulate or what dpo im in..

Is testing is too early?