Hello & welcome to the forum! I am new here as well & everyone has been so nice and wise!! This forum is a blessing!
I'm sorry you are dealing with all this crud. I'm taking antibiotics now(flagyl & amoxicillin). I took cipro in the hospital as well a few weeks ago and they can deffinately make you feel ill but I'm sucking it up because tomorrow is my last day on them I haven't taken entocort so I can't offer advice on that but like Kazbern said probiotics can be worth mentioning to your GI. If yogurt doesn't bother you I would buy some with active cultures and those can help balance out and rid bad bacteria.
I know the weight loss situation very well. If you are looking to maintain/gain weight I have found Ensure helps me a lot along with vitamin waters and green tea. I can't tolerate the milky Ensures and during a hospital stay in July I ordered Ensure Enlive! juice boxes. They are 200 calories, 0 fat, full of vitamins and are lactose free. They come in apple & mixed berry flavor. They aren't tastey like Kool-Aid but they are small and filling. Snacking through out the day(if you can handle it) on things like teddy grahams, goldfish and peanut butter crackers help my sugar stay up as well as my weight. I've lost about 85ishh pounds since February but that's Crohn's for ya!
Prednisone & I have a love hate relationship. I do very well on high doses but when I taper I crash & burn every time but that doesn't happen to everyone! Since your case is mild I'm sure Prednisone will help you out with inflammation control and it will probably spike your appetite as well.