How can I acheive a orgasm?

first it is stress, secondly you try upside position, where you should dominate, tty and explore everything, understand what pleases you. this should solve your problem

I think you're pressured, that'll be a possible cause. just try to relax, enjoy, and feel it. :)

Yeah. I think that if you have gotten them in the past and aren't getting them now, you are probably just stressed out or your mind is elsewhere. Is there something that is really bothering you/stressing you out? If so you might have to come to terms with those problems first. Do you feel connected and comfortable with your boyfriend lately? You need to emotionally connect, relax, (maybe take things slower) and just enjoy the way it feels, without worrying about when you will have an orgasm. It will happen again, I'm sure.

It sounds like you are over worried and adding pressure to your self to make it happen. Take a nice long romantic soak with your man with out planning to do anything more, then have a really romantic sex free evening. Use candles and bubble bath strawberries the whole works and just explore one another with no expectations on each other. Maybe after the bath go for a romantic walk and just chat or go out to dinner or eat in but make the evening romantic and also get your house if you stay in really cold until your slightly chilled and then maybe put a blanket and some pillows on the floor and play truth or dare and come up with things that neither of you know about the other. Sometimes you need to connect emotionally with a guy and see his softer side to get the fulfillment that you and he desire. Let me know if my advice helps any :)