Talk to General Physician on Low Blood Pressure

Assalamualikum. I'm facing the issue of ery low blood pressure. 3 hours After having supper, I felt cramps in legs n numbing sensation, when I checked BP it was just 99/50.now it's 102/58 since morning till evening even after having 4 boiled eggs, milk, almond, etc. After evening now it's come at 112/68. I want to ask that What could be the actual issue? Why it remains low even after eating too much? Also having severe headache, legs pain, cramps, numbing feeling in foots, head. What should do? Took Nims 100 mg too before half an hour ago.