how to get back data that has been written over?

Hi, I had data that was over written on my new I phone by the old contacts that were in my I cloud from 2012. I didn't read the warning when I plugged the I phone into my computer. I only wanted to store the new pictures on my computer from my I phone and managed to back my I phone up 2012. I lost all my new born baby pictures and other things. Is there any way to get the data back? I didn't back up the new I phone to I cloud.