Could I be having twins?

So I am 5 weeks pregnant and die to an ectopic pregnancy 3 yrs ago I always need to go do lab work. I have a 2.5 year old healthy daughter and I just found out I am expecting my 2nd time. I went on Thursday at 5 weeks to get blood drawn and RN told me my results. She also said my hcg levels were at 2453. Which are high for 5 weeks. They scheduled me for an ultrasound in 2 weeks. Could be it be that I could be carrying twins? My grandma had twins, and I've heard it runs on the mothers side and it skips a generation.