Hi My Son Is 7 And Sun And Mon Night

Hi my son is 7 and sun and mon night woke during the night he had I think a gastro bug the previous thurs I took his temp last night and it was between 34. Something I can't remember but was very tired didn't want to eat was too tired went to bed at 5:30-7pm woke had half a piece of toast then went back to bed till 5:45am he seems fine today but someone said he temp was very low just wondering if I should be concerned?