Should I try Cellcept?

Sorry, this post is a little long. So because of my Plaquenil issues (see other post; makes my heart rate high) my rheumy suggested Cellcept.  I'm so nervous about taking this.  For one thing, it seems like this a really hardcore drug and that it's for people with a lot of complications.  All of the tests I've had done --blood work, echocardiogram, holter monitor-- show that I'm healthy. So the plaquenil has been working fine in that aspect.  Another thing is that I'm beginning to wonder if it's the plaquenil at all because of reactions I've had to other things.  I had an odd reaction to prednisone (20mg)-- it's not supposed to make your heart rate go up, but mine did, to about 100 (though it went down after a while).  I took an ibuprofin during the period I was off Plaquenil and my heart rate went up from the 70's to about 90.  I just took a tiny 25 mg of zoloft (first time) and my heart rate definitely went up and was more pounding, and actually skipped a beat, feel like I have some chest pain now.  It seems like I'm having weird reactions to a lot of meds, so would Cellcept be any different?  The only thing that hasn't produced a difference is Tylenol.  It's all extremely confusing and no one seems to know what to make of it.  I'm leaning more towards not going on cellcept, and enduring the plaquenil for the time being, but has anyone else tried it?  Or does anyone have any advice about what could be causing my symptoms? Thanks.