How old is your hen, put vitamins in her water. If shes not eating a drinking, you should consider tube feeding.
https://www.backyardchickens.com/t/805728/go-team-tube-feeding
Put her in a box with towels to support her on each side so she doesn't flip on her back. I am not sure why she gets on her back. Does she appear to be seizing?
Go to #3 of this thread for Valbazen.
https://www.backyardchickens.com/t/408405/eew-tapeworms-where-to-buy-small-quantity-of-valbazen
Get a syringe to dispense it to the chickens orally, vets has them or the pharmacy. Tap worms are aparently hard to get rid of, you will need to scoop up the...
DE is not effective against the bugs.
Several things to check, do an internal exam in her vent to see if she has any broken egg shells and or an egg stuck. Where there is some blood, maybe a broken egg. Check her crop to see if its flat, best time of course is before they eat, looking at...
You can also treat with sevins dust and again in 7 to 10 days. All your birds will need treating as well as completely cleaning your coop and treating. Also treat for worms with Safeguard. Lice you can see, do you see the bugs? Is that blood on the right in the picture?