I had unprotected sex on the last day of my period. can i be pregnant from precum?

Unlikely : You can become pregnant from precum but it is unlikely to become pregnant from sex on the last day of your period unless you have a very short menstrual cycle such as 21 days menstrual cycle .

Maybe: Regular menses is a sign of continued ovulation.If ovulating, you can become pregnant. This can occur any day of a woman's cycle, including during menses. Those with irregular cycles would be at the most risk, decreasing if you are very regular. There are " NO SAFE DAYS" if the outcome matters.