First of all, my ds spent 3 weeks in NICU and SCBU after starting seizures at 12 hour, we didn't know for a while wether he would live. it took a year for me to start processing things, he has some sn and the first year was lots of worry and concern. After a year when things calmed down I got flashbacks, anxiety (well worse than what i had), excessive fear of losing him, depression and was diagnosed with PTSD (although this was complicated by chid abuse, another matter)
All I want to say with all that rambling is that it is normal for these feelings to come out now, after year.
With hindsight (and everyone has 20/20 vision with hindsight) you may have done well to go to the doc and be signed off for a few weeks.
If you told a manager in confidence that you were not coping and they have blagged it on to anyone else that is potentially a disciplinary matter and i would raise it as such with HR/head office. Lodge a grievance.
And maybe still go to the doctor now, to get some support (maybe counselling) and possibly a sick note.