First I'd change thread. I mean a different spool of thread on top and bobbin.
Then I'd check to see if you should lead the thread from the bobbin the other way..if you're bringing it up to the top from the left of the bobbin, do it from the right.
I did that with one of my sewing machines, no matter what the manual said, it worked.
Have you changed the needle lately? Might have a catch on it. I had one so big it cut my finger when I ran it down the needle.