my ds #2 did growth spurts at 10days, one month & has just finished one at 2.5 months, & I'm pretty sure my ds #1 also had his more than 10days before the "average" time too, so 5 weeks is very normal.
I have also noticed that they seem to sleep better & you feel like all is going well just before the growth spurt, so it sounds like your lo is there!