Twins at 8 weeks,Can you tell?

Is there a way to tell if your having twins? Im eight weeks pregnant and this will be my second child. My back hurts a lot, my boobs are tender,i crave diary,i feel nausea a lot(never throw up),and i could sleep all day if i was able lol. I gained a lot of weight between my first pregnancy,so im 5'6 and 180 lbs(used to be 120 :/) but it seems my jeans are all ready becoming snug,and it seems my belly is getting round....idk i have one set of twins in my family that i know of and my aunt had them at 40. So could it be twins? Are there symptoms?