I had mono as well about 4-5 years ago and once you get it, it never goes away. I am sure this contributes to your immune system not functioning well (as well as mine).
The pancreas thing makes sense and is a widespread problem with people who have digestive problems. I take homeopathics that contain pancreas so this helps my digestion. I took some products that specifically helped my pancreas by standard process (I believe it was zymex II).
The VSL product contains 450 billion cfu per capsule so this is a medical grade probiotic I believe. Likely should help things along…
Eggs can be a problem from my experience as well and if you reduce them you likely will feel better. I basically just eat them in the breads only now.
Things take time from my experience but if you address these problems properly, you’ll feel better within a few months.