Why do I feel super groggy whenever I become lucid?

Recently, whenever I enter lucidity, I become super groggy, as If I just came off anesthesia after having a surgery. It becomes very hard to move, like my limbs weigh 100 pounds. I can barely see, my eyes are closing as if I am right about to fall asleep.

I can fight this feeling, and eventually I become less groggy/tired, but it definitely takes some fighting. It is kind of annoying, because it has been happening whenever I become lucid.

Does anyone else experience this or know what this is?

Hello. I don't know for certain what you are experiencing but I've encountered similar. If I become lucid via WILD or close to it, I sometimes experience an in dream sleep paralysis-esque feeling. This often includes a groggy, heavily drunken feeling that, initially, I try to slug my way out of. I assume it is because sleep was not deep enough as dream state was entered. I've learned now that I simply have to CAW (Calm myself - Anchor by touching something in dream - Wait for the the feeling to pass or the scene to stabilize).

I want to say this is probably sleep paralysis. If you think about it the human body was not meant to wake up during sleep. The brain prevents muscles from moving and elevates the threshold by which a stimulus would normally wake you up, and then we go and work to deliberately try and do the opposite. I think 90% of my lucid dreams are dreams denied of "physical" movement, and I place special emphasis on that physical experience because a dream is more subjective in nature. The brain is at a crossroads because if you are "awake" then why are you still dreaming? Most of my dreams tend to end whenever I get lucid as if to correct some mistake. That being said, when I lean into the dream that physical restraint begins to dissipate. Sweven's comment about anchoring is true for me as well, and you'll see many posts and threads around here encouraging people to ground themselves to the dream, either for enhanced clarity and/or to prevent waking up.

Edit: I forgot to add that performing a mental action is also a valid solution. I don't physically move in the dream but I will myself to some space within the dream.