Woo! That's really nice to hear! You're really lucky haha I remember for me during my first week while my body was getting used to it I was feeling really nauseous and couldn't sleep lol.

Also like @FlyingSquid@lemmy.world said I agree you should be careful as it is unusual to be feeling better that quickly. There are many reasons that could happen tho, the obvious one is placebo (but who cares really if you're feeling better); second one is that the desicion to go get antidepressants has had a positive benefit to your life and made you feel like you want to make even more progress, in turn increaseing your happiness; third one is mania (extreme euphoria) which is extremely unlikely, but a dangerous potential side effect of anti-depressants and you probably need to call an ambulance if this happens; and finally fourth one is that it really has just worked extra quickly for you, which is unlikely but not impossible!

So whatever the reason is I'm glad it's working out for you, just be mindful of your emotions but don't worry too much as you'll probably be able to tell if something is seriously wrong.

Good look for the future :)