Have you had your thyroid checked? Not just TSH, but T4 and T3?
If you already have autoimmunity issues, maybe you have Hashimoto's thyroiditis, which is an autoimmune disease where the body attacks the thyroid. Thyroid problems cause tachycardia, diarrhea, gas and bloating, anxiety, depression, swelling, painful joints, exercise intolerance, insomnia, weight gain, weight loss, along with a hundred other things. They should check your thyroid antibodies for this.
Another possibility is Crohn's disease, which is also an autoimmune disorder where the body attacks the walls of the small intestine. It causes a lot of the symptoms you describe.
I hope you are taking a lot of vitamins. Either problem above, and really ANY problem with symptoms like yours, means you are not digesting food well, and heading down the road of nutritional deficiencies.
If you read up on vitamins, they always say a deficiency is very unlikely UNLESS you have a malabsorption problem, a disorder like Crohn's disease, or a thyroid problem.