Is there a possibility I can be pregnant?

My complicated situation and I had raw sex on July 20th and my period is 7 days late. I do not have irregular periods. I went to the clinic on August 2nd and my pregnancy test came back negative. I’m tired all of the time, extremely nauseous most days, and cramping. Mind you, I’ve never experienced PMS. Is there a possibility I can be pregnant? If not then is there any other explanation? I’m in this constant state of feeling like I’m going to throw up and I have no idea what it is. I’ve also had a loss of appetite. My moods have been neutral or emotional, no in between. Any ideas, suggestions, tips, etc are all very much welcome. Please no negative nancies! Thank you 🙂🥰