I can understand how difficult it has become for you with frequent thoughts of some or the other major illness in your mind. Each time getting yourself investigated and awaiting the results also seems to be adding on to your anxiety levels. I also understand how difficult it would get at times when you would be wanting to share your concerns but would keep it to yourself for fear of embarrassment or being made fun of or not being really understood by the best of friends or closest of family members. Remember a few things:
Your test results so far have not suggested Blood cancer/leukemia
Anxiety and depressive symptoms are associated with low appetite and loss of weight. Constant worrying about illnesses (that you in fact are not even suffering from) is suggestive of hypochondriacal thought process and can get very tiresome.
Mind reflects on what it gets from the environment. Too much of net surfing about illnesses is seemingly aggravating your problem. I have in fact come across many computer professionals who have started feeling stressed, adding on to their hypochondriacal thought process, following surfing about illnesses over the net.
You yourself are realizing that repeated investigations without a doctor’s advice are not required. You need to put this realization into action and avoid succumbing to compulsions of getting yourself repeatedly investigated. Instead of the pain, anxiety, time and energy spent in going through such investigations and awaiting their results, you need to put your resources for better use. As you would agree that such painful thoughts come to your mind when you have some time to yourself, may I suggest you to take out time for creative hobbies instead. You could even consider learning a new art. This would put your time and resources to constructive use. You are on Cipralex (Escitalopram - one of the SSRI antidepressant agents) since the last 7 years. SSRIs are considered to be useful medications in managing hypochondriacal thoughts. However, if the symptoms are too bothersome and you feel that the particular medication is not helping you, one could consider drug augmentation/change. I also suggest regular (as per appointments) reviews with a Psychiatrist in a controlled manner and in case thyroid disease has not been investigated so far then to consider thyroid evaluation. Activity scheduling engaging in meaningful activities, healthy balanced diet, cognitive behaviour therapy (trying to challenge negative thoughts with realistic positive ones), and spending quality time with friends and family will be helpful. You should continue with other treatments including that for tuberculosis and low Vitamin B12 and testosterone as advised by respective experts.