Where has the time gone?

So Daxon had his 6 week check-up the on Tuesday and when they weighted him he was 11lb 1.5oz! I cant believe it, he's gained 4lbs since we brought him home and is changing everyday! I was going through his cloths this morning and came across this little onesie that he wore the first week he was home and guess what? It no longer fits him! Where has the time gone??