"Once Upon a Time in America" Messed Me Up (In a Good Way?)

Okay, wow. I just finished "Once Upon a Time in America," and I'm a MESS. I knew going in it was supposed to be heavy, but I wasn't prepared for that. Like, I feel like I need a therapy session after watching that film. Seriously, anyone else just sit in stunned silence for a good 15 minutes after the credits rolled? I'm still trying to process everything. I think I need to rewatch to see everything I missed (and there's a lot to miss, it's so long!) Specifically, Noodles's face when he realizes what he's done... Robert De Niro just nails the guilt and despair. It's palpable. And the whole ambiguity of what actually happened with his friends? Brutal. I kept switching between thinking he betrayed them and thinking he was set up. Ugh, my heart hurts. I felt terrible for him, no matter if he was a rat or not. It makes you think: how can you even move on from something like that? It's not an easy watch, obviously, with all the violence and things that happen, but damn, it's powerful. And I know some people have issues with the pacing, but I actually thought the slow burn helped build the atmosphere and the sense of regret that hangs over everything. The last scene, with Noodles smiling? WHAT DOES IT MEAN?! I am so conflicted on whether it was happiness or denial. What do you guys think?! If you've seen it, def let me know! I want to hear other perspectives because I am still processing everything. Okay, I wrote this quickly and I need to SLEEP but I HAD to share my brain vomit after watching this film. Bye!