I am so annoyed at the constant requests of "what symptoms mean twins?!" And "what hcg levels means twins?!" I feel like its been way overdone already. Everyones pregnancy is different. Nausea sore breasts, headaches, hunger, exhaustion, etc are symptoms of single pregnancy aswell. Only diff is they tend to be worst with twins due to double hormones. Still you cant tell if you are having twins because you feel horrible because some ladies go through it with singletons anyways! HCG levels vary!!! There is no set HCG level for twins. How can you tell if there is twins? ULTRASOUND!!