I think Sid has a right to be jealous. Jess disappears and doesnt tell him where she is going and she is hiding out with Eric - who obviously has a thing for Jess.
While Sid shouldnt have forbade her from going, she made it way worse by behaving the way she did. It looks like they are headed down a bad road here, but I dont think she has anyone to blame but herself
I can't believe she didn't leave a note or call and leave a message for sid. That was really irresponsible and a little immature too. love the chapter though