Well, of course your dreams have special meaning to you that the rest of us can only try to guess at <img src="/images/graemlins/smile.gif" alt="" /> But I notice it's interesting that your boyfriend is in a big, solid vehicle with you, he's in control. But he's not taking you anywhere. You're just sitting there. When you decide you want to actually get moving, you decide to do it on your own. So you get out into your own car, and things go wrong. But then you realize after a few minutes that hey, you're OK anyway, and you can go on with life.
So maybe this means that in your "safe" solid relationship with your boyfriend, he's supposed to be in charge but nothing is happening. And that you think sometimes of being on your own but you worry without that safety that you'll screw up and have a disaster, be alone, etc. But that you realize that really, even if something goes wrong on your own, you'll be ok ...
Maybe the 2Dness of it was to emphasize that this was just a representation of your real life ... it's a story to tell you something ...
