Hello i just found out yesterday that i am diagnosed with mono. although i feel fine and i have no fever. is it safe for me to workout?

Yes!!: It depends what test was done. It may just have shown not that you have active mono but that you had it at some time in the past. Ask your doc to explain. The danger with mono is that it can cause your liver and spleen to enlarge and if you are very active you may bang them and injure them seriously even rupturing one or both and bleeding seriously to death.