Had my surgery August 9th....I feel your pain!! I too was feeling weak and tires ALL the time and couldn't seem to get out of bed, all I wanted to do was sleep. I spoke to my doctor and explained to him and informed him I was maybe intaking ONLY about 200-300 calories instead of the 800-900 I was suppose to be doing AND he immediately switched my to REGULAR SUGAR jello, popsicles and diluted juices, so that I could intake more calories. It made a huge difference and I felt much better. Ask and give it a try.