Struggling with Bipolar Disorder at Work

I have a story and its gonna be a long one folk.....Ive been recently diagnosed with bipolar 2 but have been feeling the effects for 4 years without having a name for it. It has been very difficult the past few years for me to be comfortable enough to stay at the same job for longer than a year. A lot of the time it is for circumstances out of my control and usually issues with management that at the time gets acknowledged but at the same time I get jokes and comments made about not keeping the same job when those same people will agree its not my fault. Currently at my job I am a part time sales lead for over a month now. From the beginning I have had issues learning and keeping up with training and expectations. I have been criticized for the very same things that are my literally symptoms such as my attention span, memory, and overall mood. A comment was made that I come into work with a good mood and by the end of the day in clearly not a good mood and that it is off putting or makes my coworkers uncomfortable to say something to me. It was also expressed that because of that I need to be better about leaving my emotions at the door... This comment was made after multiple conversations about the fact that I have a disorder that affects me daily but it seemed to make little impact. At this point I am essentially being asked to step down from my position unless I am able to work out my disorder in time to meet the expectation at the job because the expectations were not going to be changed. It was also referenced that another person who I know to be bipolar stepped down as well because the expectations and stress got to be too much. It seemed to me that the example was being set that people with mental disorders cannot and just will not be competent enough for my position. It seems that for factors I cannot control I am being deemed unworthy to do my job. To end my story it feels like I am truly incapable of being flexible, the position is too much for me and I should just step down. Any insights would be welcomed