Sounds normal to me! I can't honestly say I felt excited at any one point through my PhD until after it was ALL over (I passed my viva last November). This might have been through fear of allowing myself to ease back on work but in reality it was probably me just being too hard on myself. There's a way to go for you yet, true, but you've already done something pretty special to be here. I'd say enjoy the fear and let it motivate you but don't let it control you. Work hard, you will succeed!! best wishes