What Causes Hot Flushes With Tremors After Withdrawing From Metoprolol?

I have been take metoprolol succinate er 100 mg for about a year in a half and i abruptly stop taking them. I haven't took them in about 2 or 3 weeks and now I'm getting really sick. I get this hot sensation all over my body and then it gets cold. I took one of the metoprolol on friday and it did nothing then i took one yesterday Saturday and started feeling fine until 9 am and i got the hot sensation over my body with tremors. I am so scared i don't no what to do.