My baby still won't poop? Have any other parents experience this. help?

My baby still won't poop on her own. She is gaining weight and everything. She is 30 percent formula fed and about 70 percent is breast milk. At 6 weeks she just stopped going on her own and I have to give her suppositories (which I hate doing) but was told my the doctor that this wouldnt hurt her since I let her go about 8 or 9 days before I do this. I have made an appointment with the a gastro pediatric specialist. The doctor bills are killing me, but my baby is more important.