Take a deep breath. I feel your anxiety. My GI doctor never had me on Lialda, so I am not familiar with the drug. I suffered with UP (proctitis) for twelve years prior to surgery. The maintenance drug I took was a generic form of Colazal (Balsalizide...forgive me if spelling is wrong).
Prednisone gave me terrible anxiety and insomnia. My doctor said it was fine to take the entire dosage in the morning following breakfast, so that is what I did and it was a bit helpful as far as the insomnia was concerned.
Try eating a low fiber diet, and if possible, spread your meals out during the course of the day, i.e...six small meals daily. Stay away from caffeine and anything with high fructose corn syrup. You'd be surprised at how many drinks and foods contain it.
Ask your family physician (as my GI would not prescribe it) for something to take to ease your anxiety. My doctor prescribed the lowest dosage possible of xanax (generic form).
Has your GI doctor mentioned rectal meds? Rowasa works very well but it can be expensive. I was on Rowasa and then switched to Cort enemas and Canasa suppositories.
If you find you are eating a lot but losing weight, have your blood sugar tested. Prednisone can increase your blood glucose levels. It gave me type 2 diabetes while on it. It can also increase your blood pressure. My doctor called it the best/worse drug...just beware.
Welcome to the forum and I hope you find relief soon. This is a horrible disease and I found that all of us in here respond differently to different meds. Hope you find the med that works for you and you can stay off the prednisone after your taper. Very important NOT to stop it cold turkey because it could have devastating results.