Feeling awful, and can't pinpoint why

This has been a hard week for me. I did my 3rd round of Cimzia shots, it was the last of the "starter" shots. The next day I woke up with a sore throat, feeling very tired. Thought I was getting a cold. But it never did progress. I'm thinking it was side effects from the Cimzia. Any cold symptoms were gone in 2 days, so I didn't think too much of it.

Over all the rest of the week I just felt tired. Last night I did my first B12 shot. I'm very low on that. Well in the middle of the night I woke up with body aches, muscles hurting. I was exhausted all day long today. Just feeling like crap basically. Would a B12 shot cause such side effects?

I also went down from 5mg to 2.5mg of Prednisone this week. I don't know if it's just a combo of everything, but I'm starting to feel like all these "treatments" to make me better and making me feel worse.

I'm going to call him up on Monday and ask about that. I know he wants me off of it asap since I've been on it so much this year. As it was he wanted me to go 5mg and off, but I know my body does better to go down to 2.5 first.

Also my Potassium levels were very border low (like by one point and it would have been out of normal range). He didn't say anything about it, but I was reading that taking B12 injections can lower your Potassium. So I wonder if that's what happened? Explains the muscle aches and fatigue. Another thing to bring up, I'm going to try and boost my potassium this weekend for sure.