When I made a serious attempt in 2015, I was highly delusional but never psychotic. There had been a lot of stress for a while both at work and home which pushed me into depression and isolation. I still "talked" to people about trivial things but was paranoid about discussing my deepest fears. Since I was ruminating about these things while having suicidal ideation--they took on a life of there own. I also suddenly dropped an antidepressant I was taking during the month prior to my attempt. It is good you are posting and seeing a therapist. If you put the worst of your thoughts out there on this forum or tell them to a therapist, one of two things happens. 1) They ring true--either you or someone who effects your life has done bad things (mistakes possibly) or had bad things have happened--they are not delusions. or 2) You eventually realize what you said is a bit out there. I think most delusions and paranoia are based on partial truths. Everyone fills in information in order to make sense out of things. One of my biggest weakness is jumping to conclusions without all the facts. It is just how I process information (like the way a person skims through a textbook to pick out key facts but doesn't read it all). Since I realize this, I know I have to make adjustments. For instance, sometimes when I state to my H something I think he has asked me to do, I find that I heard part of what he wanted then assumed he wanted an additional thing that he never asked for. I also know I have to concentrate on listening to what others say rather than skipping on to the processing before they are finished.
This is a lot of rambling but maybe something here might help you? I feel like an antidepressant might calm some of the rumination (it does for some people) but keep in mind that it can be tricky (but not impossible) to stop them once you start taking them. Sometimes they do help but effect people differently...