Advice please!! Low temp

I’ll try to keep this short. So yesterday when I picked my son up from daycare he was extremely lethargic and would not wake up and when he opened his eyes it was almost like he wasn’t there he also was a little warm 100 fever. So we rushed him to the Er where his vitals were good and flu/rsv test came back normal. We were there five hours and he slept still the whole time right before we left he woke up and was smiley and then when back to sleep and his temp came down to 99. So my mom stayed home with him and he was his fine smiley self. So this evening I noticed his forehead felt oddly cold and his temp was 96.5 so I obviously googled and saw it’s supposed to not go below 97.7. Well I wrapped him in blankets and held him tight and over 20 minute Time frame I kept checking and his temp slowly went up but I could not get it above 97.7 like it was on the dot and that took a lot of work to get it there. I’m freaking out that something is wrong because google freaked me out and the last 24 hours has been very scary. Is this a normal temp or should I call the doc? Thank you!!!