Help, sex advice.

So here recently during sex I haven't been having orgasms. My sex drive hasn't changed or anything, because I do get turned on, but haven't had one the past couple times I've had sex. I just need to know what I can do to better achieve orgasms. It sucks. He also has times where he lasts awhile and other times where he finishes before I can even have an orgasm. I mean I know its normal to not have orgasms all the time, but I've been kinda stressed too, so maybe that's it. I dont know.