Feeling like a shitty mom

My 18 month old son has just been CRYING everyday from his nap. He still has a cold and that also might be why. I feel awful but god it is so annoying and quite frankly it makes me angry. I already know I am an impatient person who gets worked up over anything so that doesn’t help. He cries over everything and it drives me nuts. I tell him to “stop crying” “that’s enough” “why are you crying” and I guess the looks on my face says it all to him, that I’m annoyed and it hurts him... I’m so sad and frustrated because I know that is not how I want to be or should be talking to my child. My husband says that our son will teach me patience but clearly it’s not happening. Idk what to do...and I know it’s damaging for him for the person he loves to be angry with his emotions...I need help😞 I feel like I’m not cut out for this.