I cooked chicken for the first time? help please?

Let me rephrase the question! It's my first time cooking chicken on the stove! I always bake it but decided to cook it on the stove just like how my parents cooked it! Anyways, i cooked it for around 20min(It was marinated and in the fridge for a day). I'm worried i might have undercooked it? It was white and I didnt notice any pink spots! But after i ate it i got worried and i think "mentally" i feel sick a min after eating it. Am i just worried? It didn't taste raw either.