I think I just ate undercooked chicken?

Im really scared! I followed all cooking instructiions, and it was all white inside and the juices were clear, but there was a bit at the end which had red 'strands' in it and what looks like pink undercooked flesh. I didnt eat that part but does that mean the whole chicken was slightly undercooked? I dont want to get food poisoning, what should I do? Should I take some activated charcoal just in case? I'm really panicking! Someone help this hypochondriac here!