No! I didn't cheat on her! Stop thinking that. I love her far too dearly for something so awful. But I drank a bit too much at a going-away party (I'm leaving a large city after living here for a while), and ended up doing a line of cocaine with an old friend. I'm pretty disappointed in myself all around this morning. My question is this: should I tell my girlfriend? 

I understand it's a fairly minor point, since she's pretty cool with me doing "my thing" (she got me a bong for my birthday last year, and she knows I smoke marijuana regularly/doesn't mind), but it's important that she can always trust me. It's just that I don't want her to feel the way about me that I feel about myself today. I feel like I've let her down - this isn't the person I want to be. This isn't the man she signed up to be with. This isn't me, and doesn't reflect the way I want to act. I need her to know that I will be the responsible man she deserves in the future, and I don't want to jeopardize that. Has someone been in a similar situation? Just looking for some guidance on how to handle all these feelings. Thank you so much for your advice, Reddit; I can always turn to you for wisdom. 

edit: made way too big of a deal out of this (hangover emotions). told her, said i wasn't proud of it, turned out that it made her feel *good* that i would be honest. case closed, i'm going to go contemplate my life choices. thanks to all.
user
Went to a party, did a line of coke, feel shitty about myself and wondering if I should tell the gf even though she probably wouldn't care. Don't want her to lose faith that I'm the man she can count on.
assistant
No! I didn't cheat on her! Stop thinking that. I love her far too dearly for something so awful. But I drank a bit too much at a going-away party (I'm leaving a large city after living here for a while), and ended up doing a line of cocaine with an old friend. I'm pretty disappointed in myself all around this morning. My question is this: should I tell my girlfriend? 

I understand it's a fairly minor point, since she's pretty cool with me doing "my thing" (she got me a bong for my birthday last year, and she knows I smoke marijuana regularly/doesn't mind), but it's important that she can always trust me. It's just that I don't want her to feel the way about me that I feel about myself today. I feel like I've let her down - this isn't the person I want to be. This isn't the man she signed up to be with. This isn't me, and doesn't reflect the way I want to act. I need her to know that I will be the responsible man she deserves in the future, and I don't want to jeopardize that. Has someone been in a similar situation? Just looking for some guidance on how to handle all these feelings. Thank you so much for your advice, Reddit; I can always turn to you for wisdom. 

edit: made way too big of a deal out of this (hangover emotions). told her, said i wasn't proud of it, turned out that it made her feel *good* that i would be honest. case closed, i'm going to go contemplate my life choices. thanks to all.
user
went to a party without my girlfriend, got high, feel like scum. how do i tell her and be a responsible boyfriend?
assistant