Undiagnosed Please advise

I've been looking everywhere for answers. I'm hoping that the brace people on this site will be my best resource. Starting feeling very ill last June 2016. Searched months for a general practitioner to evaluate me and many strange symptoms. Having found one in August she gave me a preliminary diagnosis of lymphoma in September. I followed up with a second opinion at Ohio State Wexner where I was told my lymph nodes are cancer free. Now Im completely confused. I've lost 70 lbs in 8 months with a BMI of 15. I weigh 102lbs and am 5'8" having been overweight my entire life. My WBC in October was 18,000. I've been dtested for every disease and illness to no avail. My symptoms are obviously a massive unintentional weight loss., hair falling out, face pain, many enlarged lymph nodes especially in my lower back, intense itching, complete exhaustion, lower back pain and abdominal pain, severe constipation, freezing all the time, generally sick feeling, strong headaches etc. It's now Feb of 2017 I turned 5-0 last week and I started to doubt Id reach that. I'm now more determined than ever to see the next 50. I have three children that I want to share a life with. Now I have signs of malnutrition and a low immunity. Teeth falling out, skin rashes, acne and rosecea. I'm feel terrible and am wearing myself out mentally, physically and emotionally seeking a diagnosis. I haven't had a colonoscopy yet nor can they do a mammogram because Ive lost too much breast tissue and my insurance provider (Anthem Blue Cross Blue Shield) wouldn't approve an MRI to replace it. I've been prescribed medicinal marijuana to stimulate appetite and anti naseau medicine but I'm in total limbo. I have very little support and even fewer answers. I'm praying that someone sees this post and has a suggestion. What do I do next? Being undiagnosed leaves me nowhere. Please offer me any advice and/ or prayers. I'm scared to death!