Sorry, I don't mean to second-guess your choices. There's clearly some very interesting issues here, and my experience is as someone who never felt they had any serious issues with mental health. But I do think that we have this culture where everyone is expected to be OK all the time. Do you worry at all that your son cues in to his parents relationship with the drug? I mean, say it was me, and I knew my parents took a pill so that they could "have a good day" but they didn't give me the have-a-good-day pill. I would think (perhaps subconsciously) that if I was having a bad day the drug could have made it into a good one. Having a bad day would be medical now, a reason to feel like you're sick or broken.
Prozac doesn't define me. It's just something I take to address a health condition, like an iron supplement for low iron levels or amoxicillin for strep throat. My kids learned about it because they saw me taking a pill every day and asked what it was. No biggie.
To be clear, Prozac is not a "feel-good" pill, it's a "gradually feel more stable" pill. It makes my lows less debilitatingly low and more manageable -- my lows are now largely logical responses to difficult events, as opposed to randomly happening for no reason at all. The effect is very gradual and subtle: you can't really evaluate it until after several weeks, and then the "evaluation" is a conversation about whether your affect has seemed generally more stable recently. An average person taking Prozac would probably notice no effect at all, good or bad. By contrast, a stimulant like Adderrall will have a noticeable effect on anyone within minutes.
My son never asked for Prozac or for a "feel-good" pill. My kids have heard of addiction before so we've talked about pills that do make you feel good and why they're dangerous, and also "dopamine drips" like brainrot on YouTube.