Growth spurt 6weeks old

Hi ftm my baby is 6 weeks old 1 day and I was wondering how do you know if your baby is going thru a growth spurt and how long does a growth spurt last for? My lo is breast fed during the day and takes (sometimes) 3 bottles at night along with some breast feeding ... during the day she eats every 1hr to 1hr 30 min sometimes more it just depends on her... but I noticed her kind of fussy since yesterday. She has no fever or anything out of the ordinary but she is fussy.. I really need some sleep please help this first time mom