My best friend is mad at me because of this...

My best friend is butthurt and is mad at me because I won't go out to drink with her tomorrow. 
​The reason why I won't is because I just got back on Monday from drinking in vegas for 3 nights for my birthday, and I went out with her exactly one week ago. I'm tired of alcohol and I don't want to spend any money, even though she offered to pay, I'm just EXHAUSTED from going out and drinking.
​She has a child and is barely able to go out, but I'm honestly just tired. I told her myself that I'm exhausted from drinking but she's mad?  
She won't tell me straight up that she's mad, but I can tell because I tried venting to her earlier but she's sending me one word texts all day & is posting subliminal posts on her social networking page. 
​i honestly think this is immature. We are both in our 20s. So should I just let her cool off? because this is ridiculous to me.