Would lymphoma (any kind) cause an abnormal full blood count? my full blood count came back as normal but feel i am experiencing symptoms (intermittent mild fever/ nausea when eating/breathless/fatigue)

Need to examine: You appear to be under the care of a doctor who probably examined you and knows more about your health. She/he would be in a better position to explain your findings and symptoms. It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity at tolerated.