I'm sorry your rabbit is doing worse. You may want to consider changing the antibiotic to something like the Zithromax. If the head tilt is being caused by an ear infection, the baytril may not be working. Also to keep in consideration is using the steroids, but I'm a bit nervous about using steroids in rabbits, so I would only do it as a last resort. But at this point it may be something you may want to try.
The meloxicam is contraindicated in a case of kidney failure, but it's hard to know if your rabbit is experiencing this without additional testing. If you still want to try it, can the pharmacy make a suspension syrup with the tablets? That will be the easiest way to get the correct dosage and administer it to your rabbit. Usually for rabbits the dog dosage of metacam syrup is what is used, and the concentration in that is 1.5mg/ml. So if you were going to have the pharmacy compound that for you into a suspension using a 7.5mg tablet, you would mix about 5ml of the syrup with a crushed 7.5mg tablet to get the 1.5mg/ml suspension. Usually a cherry flavored syrup is used. Once you have the suspension, the dosage range for rabbits is 0.1-0.2mg/kg, but this is considered the low dose. I've read of a therapeutic dose of 0.6mg/kg being used in the UK for rabbits, with the frequency being twice a day. If it were me, that's probably the dosage that I would use. So to get a 0.6mg/kg dosage from a 1.5mg/ml suspension, you would give 0.4ml(cc)/kg. You can give at the same time as the antibiotics, and I've read accounts of meloxicam being used longterm, for rabbits with chronic health problems, so you should probably be able to use it as long as is needed for your rabbit to get better. But if you decide to give the steroids, you
shouldn't give the meloxicam until, I think, a day or two after you have stopped the steroids. But I'm not exactly sure on the amount of time you have to wait after stopping the steroids, so check this with your vet. Keep in mind that I'm not a chemist or vet, and am just making these calculations and offering recommendations, from the little knowledge that I have. Double check the math, and if possible, check with your vet as well, to make sure all the dosage info is correct. You can check this link for the recommended dosage for meloxicam as well.
http://www.medirabbit.com/Safe_medication/Analgesics/safe_analgesics.htm