Delayed periods after ipill. Pregnancy?

Hello doctor!! I was involved in sexual activity on 16th Jan which was my 5th day of period. I took an ipill within 26 hrs just as a precaution as there was no ejaculation. On 24th Jan I had bleeding which lasted 3 days. I was again involved in the activity twice on 12th Feb and 20th Feb but this time there was no penetration.  My last period date was 12th Jan. Since then I haven't had my periods. I took pregnancy test on 27th Feb and also on 2 March that is today. Both were negative. Today doctor has prescribed me primolut n tablet with a dosage of 9 tablets in 2 days and then wait for 10 days. My question is if I should start the tablets or wait for my periods? Are there any chances of pregnancy? Also I am on hypothyroid medication.