False pregnancy symptoms

I have been ttc for 3 months. First time ever trying, never been pregnant before. Last month my period was two weeks late with heightened sense of smell, swollen breast, crazy cravings and extreme nausea. Then i had a 3 day period with no cramps but a kinda heavy flow and all my symptoms disappeared. Today im late again and starting to eat and pee every two hours :/ i took a test and it said negative last month. Could i be jus stressing myself into symptoms or is my body adjusting to the possibility of becoming pregnant?