Feeling Sleepy and getting chills with Lamictal


I've been diagnosed with Epilepsy since I was 12.Now I'm 14.First medication My neurologist gave me was Trileptal ,but I had a serious allergic reaction to it and it was discontinued. then she prescribed me Keppra .I've been on Keppra for about 1 1/2 years,I was on a low dose(750 twice a day) when I first took it but now I'm taking 1500mg twice a day since I had 2 more seizures. Then I had abt 4 seizuress and she added another medicine which is Lamictal.I started taking it a week ago ,and now I'm feeling tired,and sleepy all the time.I get these chills too. is it a serious side effect? Should I call my Doctor?