I'm a little farther along in AFF than you, but I still get nervous. I've mentioned it in another thread, but before the first non-tandem I ever made (it was just the 2 AFF instructors, a camera flyer, and I in the plane, along with maybe 2 or 3 experienced jumpers that kept to themselves at the front), I nearly started crying. They were set to video parts of the ride up, but I actually had to ask them to turn the camera off because I couldn't even think about trying to joke around with them (you know the usual stuff... "Wait, you're taking these two with you? Did you sign that extra waiver?")...
Then I was fine again, but for the 4th jump, I was freaking out again. I was afraid that I was going to lose the instructor because I am more than 100 pounds lighter than him, so I thought my fall rate would be dramatically slower, or that I wouldn't be able to stay stable. With the help of the lovely folks on here though, I quickly got over that and realized that I was simply being a lunatic, as usual.
I'm still a little afraid, but after each "milestone," it's like I conquer a new fear, feel better for a few jumps, then something new pops up. LOL But it's not a bad thing because I definitely don't want to be complacent!!! Best of luck, and I'm sure your fear will lessen over time!