Early signs of pregnancy?

Hello ladies! So yesterday night I got these weird uncomfortable bit not painful aches in my tummy like I had Just done sit ups for a hour straight. I Also developed slight cramps. Well this morning and on to this afternoon I have a small headache with mega mega nausea. I have not thrown up but I have come really close. I also have heartburn and a slight loss if appetite. Did anyone have any of these symptoms? Can I be pregnant or something else?