Is this normal?

Is it possible to be pregnant with no early symptoms!? I took a test the other day & it was a bfn. Af not due until another 4 days(maybe BC cycles been irregular since TTC) and I had a single spot of darker red blood last week. Not sure if I tested too early but I'm still thinking I'm preggers. Only thing I really noticed was my cm changes and aversion to chicken. Now see I don't get sick off it I just stopped eating it. Made dinner and couldn't even eat it. Hubby and I changed our diets to help conceive better and even walk twice a wk. We've been trying for 5-1/2 months. Just relying to figure out of its a possibility to not have symptoms early on