Thank you for your query at DoctorSpring.com
You have symptoms or palpitations since last one week with some giddiness. Plus a history of weight gain in last few months. First we need to ascertain the nature of palpitations. You need to get an ecg to detect any abnormalities of heart rhythm. If it is normal you could get a 24 hr holter examination done to capture any heart rhythm abnormalities. A 2d echo to rule out any structural abnormality of heart is advisable. Anxiety may also be a cause in absence of any serious structural abnormalities.
Feel free to discuss further,
Dr Vivek Mahajan