Problems during pregnancy. Doctor.

I am 28 years old and 4 months pregnent with twins. The initial 2 and half months went very smoothly. Since after 3rd and and performing NT twin scan feeling very uncomfortable with some symptoms. The scan result was absolutely fine said by doctor. Right now I am having head reeling, acidity, waist pain, suffocation while breathing, headache. Morning sickness is very high and having severe waist pain. Not being able to sit or sleep in one posture for more time. Each having head reeling for 5mins long,then feeling fine. Mostly in evening acidity starts with headache. I have heard women find more comfort during 3-6months of pregnancy. In my case its just the opposite. Till 3months everything went fine, after that problems started. Asked my doctor about this, but she is telling its all normal during pregnancy. Please suggest are these symptoms normal or I should take this more seriously and consult anither doctor.