Propranolol and Venlafaxine together

Has anyone heard of Propranolol and Venlafaxine causing breathing difficulties when taken together? I currently take only 20mgs of Propranolol a day. And I tried adding Venlafaxine, first night 1/4 tablet, second night (Sun) 1/3 tablet and on Monday I felt like my breathing was depressed, and I wanted to hyperventilate to get more air. This led to what looked like a panic/anxiety attack, maybe it was, but it started because of the breathing.

I went to the doctors today and was prescribed Citalopram. But I am wondering if the problem with the venlafaxine was just that I shouldn’t have taken it with Propranonol?

i am unsure about Citalopram because Venlafaxine is an MAV med, and Citalopram isn’t. Is it?