Just a reminder to anyone struggling, the sheep succubus is basically a curse (I mean she DID say she was gonna drain you to a husk). Every orgasm she has drains max hp from you. I do not know if this can be countered or prevented, but when I noticed I restarted and all was great after.
Permanently draining you (even with resets fixing it) just sounds like a bug, I don't think any dev would be bonkers enough to intentionally punish you for having sex in a sex game, especially one where it's mandatory to max all her poses.
If it was up to me, I'd add a purple flame/electric effect on the end of your bar that takes up more and more of it with more sex with her to signify how much she's affecting you, and have it recover over time (to make it more obvious she's draining you.)
Plus maybe have it so she can't drain you if either of you are pregnant (like maybe she's too busy being pregnant that it's throwing her off (since it's clear she probably doesn't get pregnant very often), or if you're pregnant, you just have too many souls in your possession and it's acting as a defense? IDK, whatever fits the lore better, I guess.)
Also maybe if she likes you enough, you can tell her to stop draining you? It'd finally give a use for that chat system, too.
Then again, I haven't actually noticed her draining stats because I hate having sex with her, all the sex acts with her are so short that they're no fun, and the constant draining just makes me feel like I'm missing something, so I always cheat her pose levels to their maximums, put her in the purity room and just ignore her forever.