Implantation?

So I was supposed to start my period a few days ago which is normally heavy and a lot of bad cramping. But I've only been barley spotting with mild cramps. The spotting is a light pink/ brown and I've only had to use a light panty liner... this is very odd for me and not a normal "period". I've also noticed that certain smells make me nauseous and I was getting really dizzy last night trying to sleep and slightly nauseous, but I don't know if that's all in my head. I did take a pregnancy test this morning but came back negative. Could it still be too early to test?