Period start on 5jan, end with spotting on 7th. ejaculated inside on 10th. took prostinor2 13hrs later. 2nd 12hrs later. what are chances of conception?

Low: The fertile window for a regular 28 day cycle is usually between days 10-18 (especially days 12--15) so depending on your average cycle, it is likely that ejaculation did not occur during your most fertile time. Prostinor-2 when taken correctly, which it appears you did, is about 85-90% effective in preventing pregnancy. Taking these two factors together, chance of pregnancy is likely quite low.