Could it be prednisone, imuran or simponi?

For the last couple weeks every night around 5pm I have been getting really red cheeks and generally feeling yucky for a couple hours everyday.
It is something I have noticed since starting back on prednisone this time around, but I feel that's not it.
I take my prednisone every morning about 6am, but I take my imuran every evening around 8pm. So that makes me feel like that is the time of day i have the least amount of imuran in my system, so I feel that could be causing it? Honestly I have no idea, but it's at the point its bothering me enough I thought I would see if anyone else has had something similar happen.

It's always something silly I completely overlooked. I just started the iron supplements about two weeks ago, so I think you found my answer. Thanks