Could I Get An Infection From A Cut On The Foot That Needed 12 Stitches Along With A Tetanus Shot?

I cut the bottom of my foot on Saturday night , not sure what I stepped on but the cut was pretty deep and got a lot of grass and dirt in it. Got 12 stitches and a Techna shot. My foot had no swelling and was looking better this morning, went to work and never propped my foot up by the end of the day it had swelled up. I was given AMOX CLAV 875 mg and CEPHALEXIN 500 mg could I be getting an infection. Troy