Body is feeling weird

I've been very constipated for about 3 weeks now , and feeling nauseous here and there . I had unprotected sex , but I haven't missed a period since then . My period came on on time a week after having unprotected sex. A week before my last period I started feeling constipated , which rarely happens . My period comes on in about 7 days, I'm not sure what's going on with my body .