I needed weekly Humira when I was on it. Also, switching to a different biologic is not a bad idea. I am having good results with Remicade right now. Hopefully, the azathioprine will help, but it generally should be started before you go on a biologic. You may have already developed antibodies against Humira, so it may not work.
I would also prefer rectal steroids over Entocort, but a number of folks here have had decent results with it. Is your doctor thinking you have Crohn's now? Entocort is common for Crohn's.
Jan