Forgetfulness and stress. My stress?

I keep forgetting  specific details like names, dates, years, time ,but I tend not to forget important things like appointments, formulas, etc. I have enrolled into a master's course after a long gap of 12 years and am really finding it difficult to memorize lessons for a long period and am very stressed due to that. previously, I was diagnosed with depression as I was losing sleep and was prescribed with escitalopram oxalate which I continued for about 3 years and have discontinued it as the symptoms now are not there anymore.I also was diagnosed with mitral valve prolapse with mild regurgitation. I tend to get stressed very easily and on those specific occasions, I lose sleep at nights. Are all these diseases/ symptoms connected? How do I get over the forgetfulness and lower my stress ?