No need to worry! Certified Nurse Midwives carry pitocin
Almost all Midwives (CPM, CNM, LM, TM) have either herbs, pitocin or both to control bleeding. If there is something wrong that they can't deal with they will either call 911 or drive you to the Hopsital themselves. I would discuss this with your Midwife, tell her this is a fear and what she can do about it if it happens. The Baby Catcher by Peggy Vincent is a book about Peggy who is a Midwife and its pretty much all stories of her births that she attended. I think its a great book to read because it addresses these same fears and problems people have. I am also going to have a homebirth with my next baby and this is a fear of mine aswell, even as being a student Midwife myself. Its completely normal to have fears or doubts, just make sure you discuss them. Good luck to you!