Hi,
I am new to working with git and SourceTree, so I need some help. A few information up front: I work together with another collegue on a shared git repository. I made some changes to some files and then commited my changes. When I wanted to push my commits, my colleague had already pushed some other changes, but I didn't pull them before I tried to push myself. So Sourcetree opened up another branch. I wasn't sure how to merge the new branch with my local head without losing my own changes, so I tried out a lot of things including stashing and resetting commits. Now I am pretty much clueless what to do to get everything back to normal without losing my changes. Here is a photo of the current status:

Thanks for your help.