Irritable

My girl is 6 months and me and her dad have got sore throats and are run down. Last night she was awful going to bed which she never is, I've checked her temparature this morning and it's 37.7 and I've just given her the first bottle today, she usually has 8oz but has only had 5oz. Could it be a sign that she is unwell? Or could it be teething? Should I give her calpol? It's a bit contradicting cause the thermometer beeps red whne it comes up with anything that's 37.5+ but online it says 38+ is a high fever.