Help!

Monica
I'm not exactly sure what topic to add this to... But I really need some advice. Me and my boyfriend had sex 4 days in August. We didn't use a conform and the one time I definitely think I was ovulating. I got my period though but I'm not totally sure if it was my full on actual period. It seemed... Different. In August I had a lot of weird symptoms such as terrible mood swings, nausa, terrible headaches, very tender breasts, and bloating. It went a way for a couple of weeks but now.. My acne is terrible! My boobs are hurting again and my mood swings are terrible. I didn't think much thought about being pregnant until last night when I got this weird pinching on my right side again. I'm so confused as to what to think at the moment. Please help!