Talk to General Physician on Sudden Weight Loss

Sir i have lost almost 5 kg in past 3 months, without even trying to reduce weight, before that i have a problem of lower back curve and a little problem in cervical ... so i was taking meds from months osnate-d and methycabal as dr suggested me to take, so i want to know why i am losing my weight ..and today when i woke i had dizziness and head spinning problem all day ..when ever i lay down and take left side it starts.