Can I be pregnant if the condom slipped off but it was sticking out of me ?

If pre-cum/pre-ejaculatory fluid leaked inside you as the condom slid, then yes, pregnancy is possible.
He should always hold the base of the condom on his penis as he withdraws.
He should never continue once he has either started to lose his erection, or ejaculated. He needs to wash & put on a new condom if he wants to continue.
Another tip is to always nip a couple of cms shut at the tip of the condom, as you roll it onto his penis, so no air gets trapped. This leaves a place for him to ejaculate without the condom splitting.
Are you near your ovulation?