Ptsd? ex committed suicide i have nightmares each night, randomly break down, avoid situations that remind me of him? always on my mind, always upset?

Very possible: Ptsd manifests more clearly as producing nightmares, flashbacks or memories of the event which caused terror or horror. Also numbing or detachment and avoidance of situations or reminders of the event. It can produce anxiety, fear, insomnia, agitation. Some people are more resistant while others, particularly those with prior trauma, are more at risk. Prazosin is an excellent drug for nightmares.

I am sorry for your : Loss. You could be having post traumatic symptoms or you might meet criteria for the diagnosis of post traumatic stress disorder. Horrific or life threatening experiences can lead to ptsd. A psychiatric evaluation can help to determine more accurately what is happening. I hope you have a good support network. Therapy can also help with this type of very upsetting loss. Take care.