Chest discomfort & weakness while walking, but ECG normal should I worry?

32M, overweight with anxiety. Recent ECG was normal and I had a TMT last year that was also normal.

While walking, after some time I felt chest discomfort, back-of-head pressure, weakness and it got a bit hard to talk. I had to slow down and take deep breaths.

Could this still be anxiety or low fitness or is it worth repeating a TMT or doing further tests?

Has anyone experienced something similar?