I was also on losartan at 50mg and my consultant added the amlodipine for an evening dose.How did I feel ? Pretty awful !
Advised to stick with it and in fairness after about 6- 8 weeks the side affects had reduced and gone completly by weeks..
Not a pleasant experience.
Bottom line is my bp is around 135/75
compared to 185/90 previously.
Feeling fine now - no weight gain - lost a stone early on due to lack of appetite, now back to 'normal'.
So in my case persevering did work out for me.
Good luck !