Happy Thanksgiving!
I would give her the Calcium for a few more days. Extra for a short period of time shouldn't hurt her.
If you think she's working on expelling an egg, the extra Calcium may help.
Do keep track of it and see if she's lays an egg and starts improving.
She's only 7 1/2 months old, how long has she been laying eggs?
Reproductive issues can show up at any age.
OK Think back. She's been lethargic, then better, then lethargic, then better...when she was not feeling well, did she lay eggs or did she improve once she laid an egg?
Bouncing from lethargic to better then back again, generally I suspect a reproductive issues. Are her eggs hard normal...