I have orchitis in my right testical and am taking antibiotics all of a sudden i am feeling down and upset for no reason could this be linked ?

Issues with illness: It's no fun fighting through an illness, particularly one such as you're afflicted with. I expect a complete recovery from this- so the hard part is hanging in there with the therapy until you're better. I wonder if you might be on other medication (such as for mood?) Although unlikely there could be medication interactions- and in that case it would be important to review formally with a doctor.