Suggest Cause And Remedy For Delayed Periods

im 42 and had a sterilisation reversal 12months ago, due to financial changes i went on the mini pill for 2 weeks in april but it didnt agree with me so i stopped it and had a normal period on the 3rd of may, we had intercourse on the 24th of may and i havent had a period since, could i be pregnant or is it the pill thats caused the distruption? ive done 2 tests which were negative