Is it time to move on? Did I push her away? Or just trust issues playing tricks with me?

I am unable to tell you if there's someone else in her life, but it sounds like your drifting apart. I don't think you've pushed her away i just don't feel you two were in the same place at the same time with your relationship, people are growing and changing constantly, sometimes you grow and change together which makes your relationship stronger, and sometimes you grow and change separately drifting the two of you apart. It sounds like the latter one relates to you. Only by talking to sara openly will you be able to work out where to go from here.