Ole- Blue Eyes
I was in a similar situation until earlier this week. What you have to think about is whether you are feeling anxious over telling your employer b/c of a personal situation (ie you have a great relationship), b/c you are truly afraid of what might happen if you leave with two weeks notice, or b/c you are actually anxious about starting post-bacc in the fall.
In the first scenario, your future is your future and if your employer truly cared about you more so than the next drone (or perhaps is merely invested in you as a worker whom he/she has taken the time to groom for a higher position), he/she would encourage you to persue what you feel is you calling, or at least a more suitable career for your temperment and abilities.
In the second scenario, two weeks is definitely the standard, although your HR might try to convince you otherwise, that you are much more valued that the next guy and that your position is much harder to fill. I don't know if I'd necessarily fall for this one. By the way, after investing myself entirely in my job, giving a one month notice (b/c I fell it), being told that I was the best X my employer ever had (and I couldn't agree more, hehe), I asked for a recommendation but was then denied b'c it wasn't "firm policy." After some research, I found out that there was a grain of truth in this b/c one could potentially sue over a bad charcter reference which deters one from getting a future job, position, etc. So, if you're really hankering after the rec, do your research first and make sure that your employer would be willing to write you one at all.
In the third scenario, I had pangs of doubt (pretty brief but pretty intense) over starting on the long road to med school. What triggered this, was thinking about how I was going to give my notice and when. In the end, I got over it, quit and now being more relieved and relaxed, I can focus my attentions on waht truly matter: investing in myself voer the long run, not worrying about what a few people think of me now.
I hope this helps in your decision making.
Alice