Confused. Advice??

HBford2016

So my son is 5 months old and im now 5 days late. I took a test and I don't think it is positive but at the same time im so confused. I have every symptom of getting my period. On top of that i have pretty bad nausea too. I am not sure as to what is going on. He is EBF if that helps. Eats every 2 to 3 hours. Goes a 5 hour stretch at night.