Hi there friends.
I was normally sewing when out of the sudden my machine started to sew oddly, the first thing I did was to recheck that the thread was properly positioned in place, and it was, still I replaced the tread to check that it was placed right. it did not work, I don't know if it lost it's timing and I don't know how to fix it, that is why I am coming to ask for help.
This is my sewing machine


This is how the Sig sag stitches look in the front (i am using blue thread on the front)

This is how the Sig sag looks on the back (i am using white thread)

thanks in advance for the help