Is it normal to notice shedding in my 4th week using minoxidil (5%)

I've been using minoxidil 5% for 3 & 1/2 weeks since i noticed a bit of loose of density in my corners (19M) and i think i am already shedding... is it normal? How can i differenciate if it is really shedding or not? Thank you in advance Yall :)