Severe brain fog with possible MCTD

I finally found a rheumatologist after 4 years of issues who ask the right questions and took the time to go through my test history. She has somewhat diagnosed me with MCTD but is working with other doctors to confirm. She started me on Hydroxychloroquine to see if it helps. I have a lot of symptoms like my hearing is acting up, Trigeminal neuralgia, joint and muscle pain/stiffness, stomach issues, rashes, etc. The ones that affect my daily life is my brain fog and fatigue. Before this all started I was someone who never sat still. I have been creative my whole life and did arts and crafts, woodworking and somewhat mechanically inclined. I was the person in my family who people would come to for help on figuring out things because I have a very curious mind that never stopped thinking. I am not even close to that person anymore. I have fatigue and brain fog everyday and some days the fog is so bad I feel like I can almost see a veil of it. The closest to an explanation is if you’ve ever seen The Nutty Professor where he starts to lose brain function and goes dumb over time. I am forgetting simple words, sometimes can’t complete sentences. It’s difficult for me to express feelings or explain things. I am making dumb mistakes and can’t figure things out anymore. My art and craft projects have completely stopped and it’s like that part of my brain no longer exist. I work for my spouse now out of my home but it’s becoming more of a struggle by the week. I take Adderall and it’s the only thing that gets me functional for a limited time but it’s getting to where it’s not helping much. I could sit and stare for hours. If I had to apply for a job, I would be in trouble. I had a brain scan about 6 months ago when it first started but it was normal. Are there any test that can show this type of issue? I am feeling really hopeless.