Hi Sleepy,
Your BP reading isn't so unusual for ME/CFSers--but of course it is very abnormal. I got really abnormal readings on my tilt test and the longer they kept me standing the weirder they became with the diastolic rising and the systolic going down. I think these days I drop about 30 points systolic on standing for 5 minutes.
OI is kind of my barometer for how I am doing--bad day=lots of OI. Good day, not such bad OI.
I do use some great Italian cotton support knee socks from BrightLifeDirect.com. They are the house brand--Allegro and are called Samba. I found I needed to order one size larger than their size charts. They help enormously. I like them better than support stockings--more comfortable. Also use an abdominal binder on bad days.
What has helped my most is any vasoconstrictor as GlenP mentioned. I have tried a number of drugs, and as for drugs, the ones that increased norepinephrine worked really well. Caffeine also helps me but not everyone. I am not taking the drugs anymore but day to day rely on the compression socks and caffeine.
And, forgot to mention, hydration. In really bad times a couple of bags of IV saline works wonders. Or, if you can't get that, a whole liter of Pedialite (in the States--it is an electrolite drink for kids with dehydration) is a decent substitute.
Sushi