I understand a lot of your concerns

about getting IVIG at home rather than at the hospital especially!
I have done both and truly I much prefer having it done at home. Why? Be cause my dose of pre-meds is 3 benedryl and I don’t have to worry about driving home w/a benedryl fog! I nap on and off throughout the infusions and I have a very attentive and experienced home nurse who is very knowledgable] watching over me thru the whole process. I have had monthly infusions for 4 years at home without incident, while I did have an incident when infused at the hospital which had gone untended – The hospital KNOWS now what all they did wrong and has fixed it, but my trust isn’t there.
Also with my IVIG supplies [delivered the day before] is an emergency kit which I never had need to use. I’ve not had to use an ambulance for any IVIG emergencies at home, but have had other incidents and know I’ll be in the ER w/in 15 minutes of calling 911 if needed. [Knock wood quickly!]
As for your headaches & nausea [flu-like symptoms]? They are common side effects of infusions-usually helped by all that ‘hydration’ before starting and generally a combo of Benedryl and Tylenol. I’ve had tinkering w/doses of both and am now on the 3 benedryls – I can guarantee you that you shouldn’t have any sinus issues for at least a whole day after that! I have found that a good solid 2-3 hour nap after infusions helps clear the brain and body as well.
Lastly, around here, it’s usually the doctor’s office that does the initial set-up with the infusion company….pre-clearing it with the insurance company as well so, all you have to do is arrange the times and dates.
I have found IVIG has been a blessing in my life, one I fear if I had to do without would be disastrous backsliding and who knows what else?
Yes, the cost of IVIG is beyond dear – but there are programs sponsored by the IG companies that might be able to help out to some degree. To me it is worth it and comparatively cheaper ‘bang for the buck’ compared to other medications such as for cancer and the like.
Just keep in mind that it doesn’t work all the time for all people. I truly hope that it works a long time for you! You are long overdue for some relief.
Ask questions! There is a huge bunch of good people who have been around this block far longer than have I. People will help answer your concerns for sure.
Feel better and more better and soon!