A Bed wedge is another option and can be positioned several ways.
My wife bought me a wedge pillow for Christmas to help with my snoring, one night I randomly bent her over it and we've never looked back. Its this one from Amazon https://www.amazon.com/gp/product/B07QNZCR4Y/
Love it. if it ever gets beat up or lost we're buying another.
bonus: because I am snoring less we are having better sleep and have more energy at the end of the day :)
My mom sleeps with a pillow like this to help with drainage https://www.amazon.com/dp/B07QNZCR4Y/ref=cm_sw_r_cp_apa_fabc_wvv0Fb6E4NKSX?_encoding=UTF8&psc=1
I have a pillow made by the brand Avocado. I absolutely LOVE it. Best pillow I've used in my life. You can adjust the fill to your liking, so if your desires change you can change your pillow too. My mom also has an Avocado pillow in addition to a wedge pillow. She also love the pillow.
I got one with a much higher end incline like 12” instead of the 6-9” recommended. I think it puts my head with my pillow at around 9”. I find it helpful. Mine also can be used to sit fully up. I have an almost fully fused spine and so I can lay on my side on it but it seems to be just fine on my back. This is the one I got and I use my normal pillow with it:
Bed Wedge Pillow With Memory Foam... https://www.amazon.com/dp/B07QNZCR4Y?ref=ppx_pop_mob_ap_share
I highly disliked trying to used sacked pillows and other things to prop me up... it does smell a little the first night but the smell goes away
I’ve started sleep on a wedge pillow on my back though I’ve also have heard that elevated on your left side is better but I can’t sleep well on my left side on the wedge due to my back. If it’s really bad, I sleep on my couch almost sitting up. My symptoms usually are tight throat feeling and nausea.
This is the pillow I got:
Bed Wedge Pillow With Memory Foam Top - Ideal For Comfortable and Restful Sleeping - Alleviates Neck and Back Pain, Acid Reflux, Snoring, Heartburn, A https://www.amazon.com/dp/B07QNZCR4Y/ref=cm_sw_r_cp_apip_GnpsAiWzwtkOq
Edit: it’s much more comfortable than sleeping on several pillows as I tried that when I first got symptoms and couldn’t sleep. I also saw more recently that the have ones with cooling gel to keep you cooler at night.
Here is the link to the wedge pillow I got off Amazon. (Let me know if it doesn’t work) My sleeping set up is the wedge pillow, two pillows stacked under my knees and one pillow tucked in on each side of me so I can’t roll! I was debating between wedge pillow and pregnancy pillow but am glad I went with wedge. I tried to sleep without it last night just flat on my back and I woke up with back pain and felt more swollen than normal. Went back to the wedge and felt almost instant relief.
Limited-time deal: Bed Wedge Pillow With Memory Foam Top – Ideal For Comfortable and Restful Sleeping – Alleviates Neck and Back Pain, Acid Reflux, Snoring, Heartburn, Allergies - Versatile – Removable, Washable Cover https://www.amazon.com/dp/B07QNZCR4Y/ref=cm_sw_r_cp_api_glt_i_CC8JHRH08KDCZBE84F1M?_encoding=UTF8&psc=1
I also got this button up nightgown and it’s so soft and comfy!
SWOMOG Women Button Down Nightshirt 3/4 Sleeve Nightgown Boyfriend Loungwear Soft Sleepwear V Neck Sleepdress https://www.amazon.com/dp/B08BZNR9F2/ref=cm_sw_r_cp_api_glt_i_H9PGC2ZCM7JQHYJWDMY0?_encoding=UTF8&psc=1
Hope this helps!
Where do you live? Do you have the option of getting your prescriptions and ordering a ResMed AirSense 10 online from Lofta or cpap.com or easybreathe?
If not, try sleeping in a recliner until you get your machine. Or, if you don't have a recliner, get a wedge pillow. Also, you might try one of these devices...all of these things may help you get by better until your appointment.