Thank you for your query.
If you drink excessive water, you would urinate more frequently.
You need to provide me the exact details of your last menstrual period.
If you have skipped a period, a pregnancy
test will tell you if you are pregnant or not.
Fullness of breasts etc are not very reliable or confirmatory signs of pregnancy.
Your mood swings and fatigue
also are not specific for that.
Please provide complete menstrual history for me to comment on the possibility of pregnancy.
Let me know if you found the answer helpful