Welcome to HCM,
If you have gained 15 pounds during last month, you should consult a Physician for examination & investigations. If you are super stressed with your job, try for less stressful job, or acclimatise yourself with present job. You took a pregnancy
test, means you are sexually active. Your question is not very clear. Are you married ? Not taking any pill ! Do you want to conceive, but not getting success ? Now, if your periods are extremely regular, what issue about periods you have?
Wish you good health,