yes it's the tobacco, what you're experiencing is called a nicotien buzz.. and it CAN make you sick (dunno if home dude above just had a typo or what)

i wouldn't mix tobacco with weed when you're rolling a blunt anyways.. the blunt shell it's self is tobacco... also, you're not even supposed to inhale cigar tobacco smoke... you're just supposed to puff on it actually and taste it and enjoy it... the cheap ass cigars you see around, are actually dirty as hell from what i heard. the high priced cigars are just pure tobacco no additives, but the cheap ones are about as bad as cigs if not worse..