Temp denture after lower extractions/implants last week. In misery with temp. Very painful on gums & cannot eat. Have very dry mouth with sjogrens. See prostho again soon. Suggestions 4 surviving this?

On the right path. Your temporary denture should completely convince you that implants (with dentures or retained hybrids) are the best solution to your needs. You are obviously finding out, first hand, that traditional dentures 'suck' compared to the more modern solutions. And after you've gone through the healing process, you will find that, later, this entire ordeal was actually worth the discomfort right now.
Rest. Rest the tissues by leaving it out. Rinse carefully but often. Soft diet, no chewing. Smoothies with some whey / egg protein added. Applesauce, mashed potatoes, pudding, yogurt, etc. Stay well hydrated. Once tissues closed ovar, tissue conditioning (soft temporary liner) may be placed to fill-in the spaces as you heal and act as a soft cushion. Good luck. Call the prosthodontist as needed.
Initial healing. Unfortunately, the first month (although most dentists will hate to admit it) after having all the teeth in an arch extracted is very uncomfortable. Eat soft foods, drink fluids to keep your mouth lubricated and make sure your temporary denture has an accurate soft reline to minimize trauma to sensitive healing gums. Take your denture out at night to give your gums a rest.
Not uncommon. Take your pain medications as needed in accordance with the directions. Prescription medication, hydrocodone or Demerol (meperidine hydrochloride) can be alternated with NSAIDs OTC. See your dentist for temporary denture adjustment and be patient.
Leave denture out. Denture is putting too much pressure on surgical area. Leave it out till you see prosthodontist or it may compromise the success of your implants.
See Prosthoontist. It's very common to have a difficult time adjusting to the lower denture. If at all possible, leave it out. Only put it in if you have to go out in public. Once things have healed more, things will be better. Your prosthodontist should be able to place a soft liner in your denture. This will also help. Best of luck. Keep smiling. The end will be worth it!
Hope. Patience and hope, knowing that in the end all pain and discomfort will end and you will be satisfied with the end result. All questions, suggestions, advice, recommendations, etc. Should be directed to your own dentist who will have the most accurate answers for you. Feel better soon.
Symptomatic. Popsicles are good for the pain and dry mouth. You can get ambesol like we use for teething babies. You can try rubbing topical whiskey on the gums (sure helpd me with a toothache).