How to stop my friends using me?

I'm really annoyed and need to vent and hopefully get advice.

I'm so sick of all my friends and even my boyfriend using me as a taxi.
I'm the only one of my friends who has a license and a car and I'm forever driving people around. If we all decide...

we want to go out clubbing, I have to be the designated driver. If I dare suggest we get a taxi or train instead everyone whinges they can't afford it and we may as well not go, so then I'm guilted into agreeing to it. I can't really afford the petrol either but they don't seem to grasp the concept that cars cost money to run. No-one ever chips in for fuel money, they just expect me to drive.
I'm going to a wedding on the weekend and had all these texts from friends asking me to pick them up on the way. I feel bad saying no when I know some of them have no other means of getting there. So I say yes. And I'm driving from one end of the city to another.
My boyfriend doesn't drive as he lost his license and he is always asking me to do stuff with him. But I'm starting to think that its not to spend time together, its cause he needs my car to do a lot of stuff. Like last night he wanted me to pick him up from work and drop him at his dads for a bit, go back to his (which is an hour drive) and id stay the night, then in the morning id take him to a few different shops to get stuff he needs and take him to work and then get myself home. I duno if I'm being b*tchy thinking that way but I can't help it. How do I stop people from taking advantage of me without sounding like a rude b*tch???

WELL FOR ONE YOU HAVE TO STEP UP AND STAND FOR YOURSELF LET THEM KNOW HOW YOU FEEL. NEVER LET SOMEONE TELL YOU HOW YOU SHOULD FEEL. YOU ARE YOUR OWN PERSON SO ACT LIKE IT. I HAD THE SAME PROBLEM IT MAY SOUND HARSH BUT IT REALLY WORKS.AND BESIDES HONEY YOU HAVE TO BE RUDE SOMETIMES TO BE HEARD.

SINCERLY; RAINBOW DIVA

In my own personal opinion you are not putting yourself first...what is the use having a materialist boyfriend? and friends who dont consider your feelings but tryna make you put theirs first? um girl are you asleep? hello you too sacrificial and even tho you seem a good girl but um sorry no good girl gets the juicy munch anymore...just a load of craps from ingrates and affiliates...ill say you break up with such a boyfriend forget love that can wait and your friends tell em all how you feel and if they still insist on you being a sacrificial lamb then hey there is the door use it, you feel and if you need more opinion hit me Fun mail me...thanks

AAARH! I was so angry. Me my friend were out at the pub and we were about to get drinks and she goes Um I think you owe me a drink and I'm like What?? Why? and she goes Well remember ages ago just after you lost your job I bought you a few drinks to cheer you up... I couldn't even muster up an answer I was that peeved. I muttered under my breath Okay so me driving you f*cking everywhere counts for nothing I spose. SOOO ANGRY!!!