Sick newborn...

So my LO has been fussy all day (well, truly all week, but worse today). He felt warm to me earlier but was only 98.8 on forehead thermometer. We went to dinner with family- he wanted to be held the whole time and wouldn't let anyone but me hold him. He hadn't slept from 10am - 8pm. When we got home I checked again as he nursed and he was 99. Checked online and this is 100 degree oral temp as the forehead ones run a degree behind. This is very close to the 100.4 that they say is the cutoff for a newborn before they start taking action. I did call the doc and got her advice but I am freaking out. How on earth do parents do this?!?!? He is only 7 weeks old! How am I supposed to sleep?

Doc said to check his temp again the next time he wakes up and if it's high I have to check it rectally. :( I haven't ever done this and I am scared shitless I am going to hurt him.

Doc also said to run humidifier in case he is coming down with a cold. I asked if it was possible if he was teething since he has been gumming at his pacifier today. She said possible even though it would be early but no way to tell unless I see teeth coming in.

To make matters more complicated he is in a week of growth- which both this glow app and my Wonder Weeks app say causes fussiness and clingy-ness.

I keep thinking the worst! I just want to stay up and watch him sleep. I am seriously freaking out. I will take any and all advice and words of support.