Am i overreacting on this!?

My hub was at work, my toddler is almost out of milk, and we only have 1 car. So, i txted hub to go grab milk after work. He said he will. Later when he came home, he got in some beers. He went to buy himself some beers, but didnt buy milk for our toddler!! I was pissed off and i ask him why he only bought beer for him, but not milk for our lil boy. He told me he forgot all about it, and that he grabbed these beers when he was on break. He didnt want to buy milk and put it in the car for hours.

He never once forget to buy things after work when i ask him to. But after working at this new place, he forgets! He told me he can do whatever he want in this new place, he can go out for hrs wout them complaining, and he can go smoke, or go on break whenever he wants. And just go hangout w ppl working there. Idk why, but im just having a gut feeling that hes cheating on me w someone over there. Hes stopped calling and txting me after he started this place.

He also told me to make him coffee, he didnt bring in his coffee mug for me to wash, it was still in the car. so i was going to go grab it, and he quickly told me not to. He said hed go grab and make it himself. Like he doesnt want me to go check the car, cause theres something there he doesnt want me to see. Its very suspicious. And he even cleaned out the car, when he never does before.

Am i overreacting on all of this? Was i wrong for being upset that he didnt buy milk?