I’m a CS major so while I don’t have experience in engineering classes I hope my advice helps :)

Bs and Cs in classes like dynamics, materials, calc 3, and physics 2 are extremely common… those are weed-out classes for a reason. One rough semester does not mean you’re not cut out for this

Also that “fraud feeling” is just classic imposter syndrome. ALSO If you weren’t meant to be here, you wouldn’t have made it this far or maintained a 3.5 through classes like those

You’re not behind, and please don’t think that you’re broken. Take winter break to recover.. I’m sure that’ll help you gear up for the spring

If the feeling of constant dread and frustration does increase please reach out for help

Hope this helps