Girls, we've been struggling with constipation for a month now. We tried…

Girls, we've been struggling with constipation for a month now. We tried Duolac, candles, and even enemas... I only went out a couple of times during that time. The doctor says wait three months, it's not just about the digestive system maturity and all that. Is this how everyone is? Or should we look for another doctor, change the formula (we use S-V), get blood tests, etc.?