Dear Madam, I will try to resolve your query from whatever information you have provided me. 1. The egg release is some where midcycle, 14 days prior to the next expected cycle. It has got life of 24 hours and sperms are active for 72 hours. Thus a week around the day of ovulation is fertility window. So you must have realized that pregnancy due to the intercourse on 5th day of menses is practically improbable. One more advice at this juncture - please do not perform intercourse in the bleeding phase of menstruation. Blood is a very good medium for bacteria to grow. Such infection may ascend to the tubes and cause tubal blocks leading to infertility. 2. You are on medication for Hypothyroidism. May be your dose of Levothyroxin needs to be adjusted. In hypothyroidism, the weight increases. Please get your blood examined for T3, T4 and TSH. 3. Report to your Gynaecologist and/or Endocrinologist for evaluation of Thyroid. I am sorry madam, this does not seem to be pregnancy, mostly looks like Thyroid problem.