My Mum did this a few years ago for her Sister.
A few days before the event, she received 2 injections per day for 3 days to promote the cell growth that they would retrieve via a blood device that is connected to both arms.
You will feel pretty much like a bloater come the last day as your blood will be pretty thick, but as for side effects my Mum had none.
When having your blood cleaned of the excess cells, you should receive an injection to counter a feeling/taste of "metal mouth", something to do with the loss of the cells.
This injection is important, if you start to have this sensation you need to let them know asap. They weren't on the ball in giving it to my Mum and she was a little unwell but this was only for an hour or so afterwards.
It takes a while to complete, so just relax. After it's done I think it's a couple of hours before your cells are transplanted/transfused into the recipient.
Mum was good to go home the same day, and next day she was as right as rain, no problems.
May be best to have a driver, or give yourself a good few hours rest after but I'm sure you'll be ok. Plenty of sweet tea and biscuits. You'll be well looked after by the hospital as you're just as important as the patient.
Good luck.
