I can see cracks in the belly, but do they go all the way through to the back of the bow?
My current hunting bow is an Osage that has a long, 10-12" long longitudinal crack like those ones that developed in the
back of the bow running right through the handle and into the bending limbs on both sides of the handle. It has a couple of other longitudinal cracks in the bending limbs as well. I noticed the first long crack just after sanding the bow for finishing. I put some super glue in it for a little insurance, and then finished the bow. I've been shooting it as my primary shooting and hunting bow now for over a year, and I'm quite sure I've put close to 10K arrows through it, or more, and it has endured beautifully. It has also been backpacking with me in some pretty rough country twice now, and endured a bit of abuse, and still just as snappy as ever. I'm about to replace it as my primary bow, but only because I love building bows and I'm getting close to finishing this year's hunting bow.
Like Don said, I don't think you should give up. I think you should just stay the course, and when you're getting close, run some super glue along the cracks for insurance and let it seep in there (I don't think the super glue is necessary, just comforting). I think there's still a good chance you can get a shootable bow out of it. If by chance it does break, you've gained some valuable experience. As I was told when I first started this gig, you're not a real bowyer until you've broken your first bow.
I really Hope this isn't the one you break, and that you look more like this when you're done
, so don't lose heart and keep at it.
Good luck!
Eric