Not sure if I'm pregnant

Hey guys I recently had sex unprotected. When I had sex I wasn't ovulating. My partner did not ejaculate but he may have leaked a little. I lost 10 pounds before Christmas and I gained it right back after the new year. Could it be because I'm stressing about being pregnant? I have been eating a lot of (snacks, sweets, pop, etc.) because of my stress but I gained my weight way too fast. A couple of days after I hand sex my nipples were tender, today I had a pain in my stomach, and and when I used the restroom my pelvic area had some pain but not too bad. I've never had any of these symptoms before. Has anybody else had these symptoms? Help please!