Getting mine tomorrow at 9:45. I live alone, so will do a shout out to neighbors prior as we take care of each other. Yet all I have seen from folks here who had had... it's just work through it. Our bodies per Dr. Campbell can go for much time without food... and I will put Gatorade/Powerade right this minute by my bed for hydration. Aches/headache expected to be minimal as my first shot! I have no idea which one I'll be getting at the mass vaccination site, even though I have googled!
I've talked to close to 100 mature adults who've had the vaccine since Feb., and have read every post here.
Overall, people are having some temporary aches and chills, some mild fevers. Like a flu shot reaction when I was 30, I'd say.
If you are mobile, walking around in your house is probably better than being still. If you are a normal portion and food consumer, maybe pick up a rotisserie chicken and a few veggie sides to keep some food in your tummy. ( or whatever you like in the way of protein and veggies).
If you feel like ice cream for 3 days, eat ice cream for 3 days. If you crave hot oatmeal, just look for the Quaker packets in the pantry.

I have had a lot of oatmeal and Jell-O heat and serve chocolate pudding I fix in the microwave. These are my comfort foods from childhood.
You probably have yours too. Be good to your body. Gatorade won't give you many calories. Pamper yourself according to your safety needs. Take long soaking baths or relaxing showers and the muscle aches will be so much better if you have any. If not, just take the soaking treatments to relax and sleep well.
I know you are strong in will and I want you to come back and tell us what you got and how it went, OK?
BTW, I wrote this to you because it touched my heart that you're alone. I had a run of kidney stones right after I married this husband, and I had gruesome probing surgeries with all kinds of stents placed and had a catheter and a metal stent taped to my leg for 2 weeks after every single surgery.
My husband, 32 years old and dumb as dirt about women, illness, and pain left me alone for over 12 hours a day.
I learned: I'd get him to bring home foods I could put in a bedside cooler along with 2 huge insulated stainless steel 2 liter bottle I kept liquids in ( I don't like plain water- never have). I'd cover most of the bed with a towel in case I spilled something, and I'd simply spend the hours reading, loving my dogs, getting up to let them out, and performing self care.
I was new to the area- Didn't know a single person- and as an only child who had been pampered all my life when I was sick, I realized my world had shifted and it was up to me to get well and get the catheter out and the stent without being sick or getting an infection ( I had a course of antibiotics of course).
So, while we are sometimes alone, we have our inner strength, and you don't even have to reach in and find yours. It's right there with you. I bet you're one of those " showy girls" who just has a teeny bit of a sore arm.
Hugs and my best wishes for your vaccine. AND no illnesses to come down the pike for decades to come.