I think that you are testing to early. 8DPO is to early to tell. You should probably at least wait until your period is do and then if it does not show, later that day you can takte the pregnancy test. If you are testing sonner thatn 12DPO you are probably just going to waste the test even though there are some women that get results sooner than that. I waited until my period did not show 14DPO and then got a BFP later that day. I felt like my period was coming so don't read too much into symptoms because everyone is different and you never can tell.
Good luck to you