What could be the reason for breathing difficulties, and extreme tiredness in a patient with a past medical history of lupus, Raynaud's phenomenon, and migraines?

Hello doctor,

I am a 29 year old. I have a past medical history of lupus, Raynaud's phenomenon, and migraines. Since being diagnosed with lupus, I have been having difficulty breathing and it was found that I have tachycardia which the doctor is treating me with Metoprolol. Metoprolol helps with shortness of breath when I am at rest but once I start doing things like brushing my teeth or getting dressed I feel out of breath and sometimes become sweaty the more I move around. I have been extremely tired and it is getting increasingly worse over the months. I have done several imaging and laboratory tests and the doctors do not have an answer for the probable reason behind this. I also have the lupus anticoagulant. I am worried because I keep getting worse, along with breathing issues. I am holding a weight in my abdomen area despite eating healthy and exercising within my limits. My toes turn blueish purple a lot more than usual. I used to run miles for exercise but since being diagnosed with lupus and developing breathing difficulty I become out of breath walking less than 100 feet. I have a right cardiac catheterization scheduled for next month but I am wondering if anything can be determined from my laboratory tests and images right now before the catheterization. Thank you.