Find a neuro-opthomologist and get good visual field tests done. Get your GP or someone to run more detailed tests (not the usual thyroid panel which is useless) but thyroid antibodies, FH, LH, DHEA, estrodial, bioavailable testosterone, test out the adrenals for metaphrines, cortisol, renin, aldosterone, sodium, potassium... There are a lot of tests that can be done - just be careful to know that they are being done correctly, at the right time of day, if fasting or not, and if the lab tech is handling them correctly. Lab error was really something that held me back.
Really, an MRI is something if it shows up but... 40% of tumors of do not. Labs are the real thing. Lots and lots of blood and pee.
The docs like to blame the stress, not realizing that the stress is coming from the inside. I had cushing's and high cortisol. I felt like I was crawling out of my skin all the time - but rather than look for a cause, I was just blamed for eating and given tests for sleeping and pills for diets.
Stress can make everything worse, but it does not cause all the symptoms you are having. If they did not specifically target the pituitary for MRI exam, you are right that they could have missed something. It sounds like it's time for you to find another doctor, and you need to be seen by an endocrinologist. It's your life. Don't feel bad about seeing another doctor. There are doctors out there ( though very few, it seems ) who are more determined to get to the bottom of things, and help you.
If nothing was found on the brain MRI, you might ask about imaging the adrenals directly. This is how my mom's adrenal lesion was found. She was (and still is) having terrible blood pressure problems, but she is 86, and it took a lot of time and doctors to discover the cause, because, hey, old people have blood pressure problems. (that was their attitude).