Growth spurt or something for worse?

For the past 3 days, my little guy has been progressively more fussy. He's run a bit of a higher temp, 99.4, on and off and is eat more often. He constantly needs to be held, and goes from being fine to just wailing his face off in an instant. He's going to be 6 weeks old on Thursday, and I know they hit a growth spurt around now, but everywhere I read says that a 'fever (I think they mean 100.4+) isn't included. Are there any other moms out there battling the same thing?