Swollen Feet & Stomach

I have had an elevated blood pressure problem for the last 13 years for which I was prescribed 5mg of amlodipine tablets . About 4 months ago , my GP suggessted that I increase the dosage to 10mgs as my BP was hovering around 140/95 . He then warned me of the side effects ie swollen feet etc as possibilities . I noticed a slight increase in my selling on the upper side of the feet making it slightly difficult to slip on my shoes . However , after flying off to M'sia from London ( 13 hrs flight ) my feet are really swollen badly such that I can't put on my shoes ... My stomach is also bloated up .. My weight has increased by 6 kgs due eating ..

What could be the problem?