Not sure if I'm pregnant or in my head?

Took my vit. With out eating oops but I have been so nauseous today I still am even after eating. I also maybe just started 8 days early according to glow.. But it was spotting but it wasn't pink it was a blood color but I put a tampon in and it's kinda bother me because it's so dry.. As gross as that sounds. Also I have been so exhausted and grumpy but idk it's because periods coming soon? Idk should I buy a test? The Ovia app said my periods supposed to come in 4 days. Help?