Bad throat, is it caused by thrush, help?

I went to the doctor about 3 weeks ago and he told me i had thrush, he gave me this medicine that i had to swish around in my mouth, i took it for about 3 days and then stopped because it started making me feel stomach sick. Then, about two days ago my throat started feeling weird, like i felt like i was going to throw up in my throat, and it makes me want to urge when i swallow? And its very uncomfortable I looked in my throat and i could see a bit of white on the wall of my throat. So is this caused by thrush? If i go to the doctor, what will they do for me?