Could I be pregnant? 15 years old?

Take a test. Since you're due for your period now it should be accurate. Some of your symptoms aren't true pregnancy symptoms but many are. The big ones are tender breasts, fatigue, and frequent urination. The hormone that basically tells your body that it's pregnant (HCG) will make you pee a lot. If you don't have you're period in a couple weeks see a Dr even if the test comes out negative. It could be another underlying condition.