Is this your trauma speaking, or do you automatically associate any sexual needs with a pathology?
You've done it twice in this thread alone.
The situation is PersonA has determined they need an anti-depressant. So one thing is 'wrong.' It stands to reason that they may be using sex as a painkilling mechanism. After all, sex feels great. When the anti-depressant kicks in, the body may determine it doesn't have to use that painkilling method anymore, hence, the decreased libido. It doesn't mean having a libido is bad, it means that the person potentially was overdriving it.
But I understand that it would have been better to ask and not associate because it's a fraction of the cases.
Either OP is confused about what libido means, or has some kind of heavy shame around sexuality.
Sex is awesome and liberating! Should be anything but shamed.
When I hear people say "it killed my libido" I always think about the fact that hyper-sexuality can be a trauma response, and if your body is healing the hyper-sexuality is most likely also reduced.
It's like when you have a disease and then read the side effects of a medication and notice that a lot of the side effects are basically also something that can happen when your overall condition is improving but still some people report them as adverse effects and then these are added as side effects to the package label.
For example you take antibiotics but bacteria can have toxins in their body, and when the bacteria disintegrate you get more sick from the released toxins. It's called the Herxheimer effect: https://en.wikipedia.org/wiki/Jarisch%E2%80%93Herxheimer_rea...
When I started methyl-B12 supplementation I also had inflammation in sinuses for weeks but it was just from my immune system starting up again and being able to attack long-standing inflammation. Someone else would've put "fever", "headache" and "stuffed nose" onto the side effects medication label of methyl-B12.