Blood pressure 90/52 and on blood thinners for blood clots in lungs, now feeling very weak.?

Go see your doctor. Go see your doctor now to find out if there is anything seriously wrong.
Depends. It depends on what your blood pressure is normally, if you've started any new medications lately, if you're using a new machine, or a number of other factors. It is also important to know your blood level of your blood thinner is. Very high levels can lead to spontaneous bleeding. You should see your physician as soon as possible.