I plan on going to school as male this fall with a male chosen name, but my legal name is feminine and I'll be living in on-campus apartments with 3 other girls (who I'm already out to). The building I'll be living in is co-ed. The girls I'll be living with are all cool with the situation.

I plan on emailing my professors ahead of time, explaining my situation and asking them to call me by my male name. The university I attend is a liberal school, but the location of the school is a very conservative area. It is a big school and I most likely won't have any of the same professors I've had in the past since I am just starting the classes for my major.

I am so scared, and any tips would be nice to alleviate my anxiety.

You're actually off to a good start it seems!  The people you're living with are cool with it and you're emailing your professors about it ahead of time (who you will most likely not have had before, you say).  I'm doing the same thing you are...only my third semester at my college XD which is small, and I'm having all the same teachers again (not to mention some previous classmates might be a bit surprised). 
I find there's not really to much anyone can really say in situations like this.  It's sort of you do it and deal with your nervousness as best as possible.  This is something that'll make you nervous no matter what, but things should be fine.  Especially if you have a good pass rate, then there shouldn't be any trouble.
Make sure you introduce yourself by your male name consistently from the start to prevent unwanted outing and confusion.  (It took me a little to begin introducing myself as Lucian).  Since it's a liberal college (as mine is) the crowd will probably be more open at any rate (it's been my experience that a lot more people than you might expect are okay with trans stuff).
I hope there was something at least minutely helpful in that little ramble ;P
Go forth, be brave, and good luck!

Yeah, I have a few questions myself related to post-secondary and such. I recently told everyone that I am Tom and that I'm transitioning and everything, so that all went well. This is my first year of university so I'm living at home just so that I can get everything worked out nicely. I'm registered and everything, I'm just waiting for my final transcripts to get the final "yes" but I know I'm in. BUT I have no idea if I can even email my professors ahead of time or not plus, at some point this summer, I have to go there and get my Uni ID which will be using my legal name and such.

Sooo I don't know if I'm supposed to email the registrar or contact someone at the admin office or what?

Also, I don't know if I'm over-stressing this but keep getting super nervous about public washrooms. Like, normally when I'm in public, I avoid using the washrooms and wait until I'm at home but I know I won't be able to do that forever. And I know for a fact I won't be able to get away with that at uni. So what should I do?

If your Profs know you as female name, make an appointment to meet them and explain. Face to Face is important because I'm a Prof and have no idea who most of my students are. They are XXX@ uni.com or on exam papers, Student number XXX.  I can assure you that 99% of teachers at Uni couldn't give a damn if you are a blue faced hippo, a girl, a guy or anything else. It is so far of the radar that only the student thinks it is important. The only time I am ever interested in the orientation and  sexuality of a student is if they come to me for help with a personal problem. I want to know then so I can give advice. Again I really don't care what orientation/etc they are, I just want to know so I can arrange the suitable help services.

If you are nervous about toilets etc have a talk with the Uni counselors and the LGBT group at the Uni. Universities have VERY strict sexual harassment rules and have lots of counselors. Finally, University life is a lot about self development. Your Profs and teachers know that; we are completely aware that our students are going through all sorts of  life development and finding out about themselves.  We expect it.  That's a lot of what Uni is about. Don't be nervous, live your life; Oh and by the way you may find your Prof is TG as well


Cindy

Haha, I didn't really think about that. I have a lot to learn in Uni, knowing that the Profs aren't anywhere near as personal as teachers in high school. XP And I constantly forget how large the student body is which means there's far more support that will actually help me in my development.

Thank you so much, you've been so helpful already. I'm definitely a lot more relaxed now than I was before.