Experiences Dropping Methotrexate, Just Taking a Biologic?

I've been on 15mg of injectable methotrexate for a long time, and my side effects have progressively gotten worse. I spend the day after my shot in bed due to fatigue and nausea. I'm also on Orencia, and have been for almost three months.

With a lot of biologics, doctors recommend staying on methotrexate because it reduces the risk of developing antibodies against the biologic, but studies indicate that that isn't the case with Orencia. As a result, my rheumatologist is okay with me reducing and perhaps eventually dropping the methotrexate dose if Orencia is working well (which it seems to be... still having some joint pain but nowhere near what I was having on just methotrexate or on methotrexate plus Enbrel; fatigue, brain fog, and headaches unfortunately are still unchanged).

I have two questions:

1) Does anyone have experiences (good or bad) to share about dropping methotrexate and being just on a biologic? I'm a bit discouraged that my fatigue, brain fog, and headaches haven't gone away, and wondering if it might be methotrexate-caused instead of uncontrolled RA.

2) Are some of you on biologics that otherwise work for you, but still have gnarly fatigue?

Thanks!