Hello My Question Is I Had Intercourse With A Friend

Hello my question is I had intercourse with a friend twice in one night maybe 30-40 mins apart and the first couple mins we didn't use a condom till after awhile we used one and my partner never got to finish he just threw the first condom away which had lil sperm in it and he didnt clean or use the restroom second time around he didn't have a condom on first few minutes once again till a few mins later he put one on. Now my question is can a pregnancy happen if he pre ejculated the second time we did intercourse ? And the following day I got my menstrual cycle . I heard that it may be possible