Hi D.,
My sons are 13 months apart and having two under two is a challenge. People say "oh they'll be just like twins!!", and that may be true once you get past a certain age but now (they're 3 months and 16 months) situations like ours are their own special thing. There are always posts on parent center, and there is a website called two under two, although they don't seem to be operating too much these days. The point is, get help from other moms because those with one child or kids 2+ years apart will not understand what you're going through. On the plus side, you probably still have all your baby stuff (and maybe maternity clothes?) and once your eldest is out of his car seat, clothes, etc., you can save everything for your youngest. Also, both your kids will be done with diapers, bottles, etc., more quickly than other families.
As far as sleep goes, we are very lucky and both our sons started sleeping through the night VERY young (6-8 weeks) and they both took to their cribs well. When my youngest was born, we put him in our room in a bassinette so that he didn't wake up our oldest. Once we felt pretty confident that our youngest wouldn't wake up and cry in the middle of the night (about 2 mo 3 weeks) we put him in his crib in his room with his brother. They are doing fine with this. I always feel guilty that I don't have the time for our oldest that I used to, and that's probably the worst part of thiis. This might be something every parent experiences though, regardless of how far apart the kids are in age. My oldest is sometimes sweet with the baby (trying to give him his pacifier, giving him kisses, etc.) and other times a typical toddler (smacking him in the face, stealing his pacifier, etc.) For the most part, our family has adjusted just fine, as I think people tend to do...
The bottom line is you will be fine!! I know when we found out we were pregnant again, I cried... not because we didn't want the baby, but because we didn't necessarily plan on having them so close! I have a very supportive husband, but no family in the area. My mom did come down when our youngest was born and watched our toddler. You will definitely need some help right out of the hospital, so plan on getting that! My husband and I have managed pretty well... I am a graduate student and teaching assistant, he works full time and just finished his degree in December (two weeks after our youngest was born!!), and we've spent a good bit of time fixing up the home we just bought in October. So, get yourself some support from other moms, and what you can from family and friends and you'll be fine. You can always send a personal email to me, if you have any questions you think I can answer. Good luck!