While an ultrasound is the most accurate way to confirm a twin pregnancy, there are some signs and symptoms that may indicate the possibility of carrying twins. These include rapid weight gain, larger-than-average uterus size for gestational age, heightened pregnancy symptoms such as morning sickness and fatigue, and feeling more fetal movement than expected. However, it's important to note that these signs can vary from person to person and are not definitive proof of a twin pregnancy. Only an ultrasound can provide a conclusive answer. If you suspect you might be carrying twins, it's best to consult with your healthcare provider for further evaluation and guidance.