Could I be Pregnant?

I'm two days late, after today will be 3 days late.

My last day of my first period was January 4 I done research if I am I would be 4 weeks and 2 days pregnant. I have been feeling like I lost appetite, which is why I question it since most people gain it. I could be eating, during the meal I feel full and I'm not half way done right after I feel like throwing up. I have theses HUGE headaches where my head feels frozen and its pounding, my heart tends to race often not sure if because I keep thinking about this. I have lower stomach cramps but they feel like cramps inside for example, you know that feeling of holding your pee? It feels like that. I also been pooping so much! Sometimes I'm constipated. Is it to early for signs? How long should I test?