Pregnant or not? And early symptoms?

I have a question with which you can help me I hope. I have irregular cycles, varying from 25 - 30 days. My current cycle started with a period of 9 days. According to Glow my fertile days would only start on day 13 or maybe 14. On day 11 and 12 I had intercourse. 
On day 13 I started feeling weird, being very nauseaus/ sick and feeling very tired in the morning. I'm now on cycle day 15 and feeling a little bit better. But still feel cramps once and a while and light sickness. In the morning I feel very tired, while end of the day I can feel confident and energetic. I have these weird light pains in my ovaries and/ or uterus. 
Could I be pregnant, since I had intercourse only on the day before my fertile window started? With my last pregnancy I got pregnant 2 days before my fertile window started as well. And could the symptoms described be early pregnancy signs? I read everywhere that it is not possible to have symptoms that early. But I somehow feel so strong about it. 
Hope you can share experiences.