Well, I think what you feel is normal, even expected. Congrats, you are one of the few people who really take parenting seriously. Caring for a child isn't supposed to be a bowl of cherries, it's a permanent responsibility. It's normal to feel nervous or inadequate. But people who take it seriously tend to be good, loving parents and they produce polite, happy, outgoing children. Your situation may not be ideal now, but you have nearly a year to plan things.
Do you and your boyfriend live together? If you don't, you might want to think about it (that is, if you were planning on marrying each other anyway). Bring up some issues to him that will make him think about the responsibility more-where the baby will sleep, etc. If he can be concerned with you and be supportive in *that* way (but it is good that he is at least supportive of you otherwise), you might not feel so helpless.