Not me but a close relative (we'll call Jane) had a gastric sleeve procedure about 12 months ago.
I can try to answer any specific questions you have, or I can ask Jane if it's something I'm unsure of.
Jane has lost around 8st but it's definitely not the easy route to weight loss like people believe. She was in a lot of pain after the operation and only started to feel a little better around three days post-op.
My advice is to listen to and abide by the guidance from the doctors/surgeons and don't try to bend the rules as it's likely to backfire and cause you issues.
One example is not waiting 30 minutes between eating and drinking.
If Jane doesn't stick to this rigidly, she quickly becomes nauseous and usually vomits. She also feels dizzy and has hot flushes. We are constantly telling Alexa to set 30 minute timers!
One thing we did notice is different signals post-op that your stomach is getting full. Jane's signals are fake yawns and sudden fatigue, and if she accidentally eats too much or too quickly, she gets "foamies" which is where the mouth fills with a foamy liquid which makes you feel nauseous (usually an indicator of an impending vomit, but not always). Cyclizine is great it you find you're struggling with nausea post-op.
Everyone's experiences and recoveries are different but overall it's been positive for Jane given she's now a healthy BMI, and she loves that she can buy clothes in any shop now!
Best of luck for your operation.

