Changed formula...AGAIN

So my daughter was breast fed for a day after she was born until we had latching issues and low supply. Hospital had pre-made Similac Advanced...no issues so I kept her on that until we started having gas and constipation problems. Pediatrician switched her to Similac Sensitive. It started out good until a few weeks ago. Constipation, gas and hard poop (I mean hard and solid). Tried Karo syrup and it seemed to help somewhat except for today. Put it in 3 of her bottles and nothing. Poor girl was screaming in pain for hours so I went and got suppositories. She finally went and I mean went. She had to of been backed up for days because when she would go, it was only a little at a time. Well I had a sample can of Enfamil Gentlease that I'm gonna try and I'm hoping it works. I just feel terrible for switching her formula and this time to a completely different brand. Any mom's have a good experience with Enfamil over Similac?