It's impossible to tell whether you're "close to psychosis". There are no warning lights with this. Delerium kicks in just like you would see with a diphenhydramine or LSD trip gone wacky - very suddenly you will not be concious of your actions and then it's all downhill from there.
Like I said, one second you can be doing fine, the next you'll be waking up in a jail cell, ICU, or hospital psych ward. I'm sure there are many stressors that will make it more likely for you to flip out. Having a high baseline level of stress in your life and using dissociatives on a regular basis as an escape is a no-no. So is dosing when you're hungry, tired, emotionally preoccupied, etc. If you choose to ignore this advice, always have someone nearby who can call the ambulance when you drop like a fly, or start trashing the place, or are too incoherent to do anything, etc.
Combinations with other amnesics/sedatives (cannabis, opioids, benzos) will also exacerbate the risk of freakouts because they potentiate the effects of 3-MeO quite strongly. And likewise, the dissociative/stimulant effect of the PCP will potentiate the analgesic and euphoric effects of opioids.
I am especially concerned when I see people talking about combining MXE or 3-MeO with etizolam or other benzos. The combination of ketamine and e.g. midazolam can be used to induce a deep anethesia that can cause loss of breathing reflexes.