Low energy after sex? How often should you do it?

Different people different results. (Kind of like introverts vs extroverts, introverts feel drained by people (but often need them to feel comfortable, and extroverts are charged by people). Some people find the relaxation they find in sex unleashes them from their burdens, and jazzes them up. Others, feel that the relaxation they feel gives them great chill. And you don't have to be one kind of person, the experience can change from time to time.

The feelings you have after sex aren't good are bad. They are natural. It's your hormones recycling, and a whole host of natural functions doing their thing.

Those feelings are only bad in PMO because it narrows your focus, dulls your vision and perspective to those around you, and acts as block from connecting to people in the real world. This can cause your real relationship to starve. Or if you are single, this can block you from seeing possible partners that exist, or not even seeking a partner. PMO can also feed negative feelings of guilt and fear for being negatively judged, which harms you from relaxing and connecting to people. However, if you're operating entirely in the real world, and your connecting, then there is nothing to concern for.

The only time you should concern yourself with this, if if you are facing some kind of performance challenge that is more important now than a relationship. Some distance athletes might abstain so they can keep their performance constant. Or those facing mental challenges like a intense test. Knowing yourself well enough to know how you perform in those cases is healthy. (Although many with such challenges feel that being in a relationship/sex is the only thing that makes the challenges worth it.)