I've seen a lot of women go through what you're going through. They think they want to keep working once they have their baby, but once they have that baby and experience a mother's love for the first time, the thought of leaving that baby is suddenly a devastating thought. It's surprising how much one can love a little person. My daughter's pediatrician had a few children, and she ended up choosing to stay home because she valued it so much - and she was a DOCTOR!!
I think you do what feels right to you. I'm a SAHM, and it's my dream job. It's also been my hardest job, though the most rewarding. I would do anything and everything I could do to stay home with my children. My husband feels the same way and does all he can so that he's the sole provider so that our children can have me taking care of them. For me it's an amazing life to be a full-time momma. I homeschool as well and love it. My husband loves it too and it fits us well and helps contribute to so much happiness that we feel.
If you're considering it, you'll probably find yourself feeling it even strongly once you hold that baby in your arms. I can't imagine having someone else spending the days with my babies...seeing the first time they roll over, sit up, walk, etc... i treasure those moments. I love to hear them and play with them through out the day. They are my babies and my dream to raise.
On the flip side, I know women who feel completely opposite in that they don't feel fulfilled in stay at home, and they find a lot of fulfillment in working outside the home. I think it depends on the person.
Follow your gut and do what you feel fits you and know that if you choose to be a SAHM, even after all the schooling, it's totally worth it! Education is great for motherhood.