In all srsfacedness:

If you're writing this post in the hopes that us telling you "yeah we feel that way too, you're great at lots of stuff, i've been through it, it'll be fine" will make you feel better about yourself, it might in the short term, but the feeling will come back.

The prevailing attitude is that one's personal feeling of "I do well in school" or "I could've if I'd put my mind to it" equates to one's feeling of intelligence, maybe even worth. At this point it's really culturally ingrained. You probably already feel like this feeling of being stuck/stupid is something you can't escape. Even knowing that it's not logical, it's tough not to get stuck in this Ne + random feeling of idiocy that keeps coming up - loop. What you need is concrete evidence that you're not an idiot.

I struggle with this school feeling when I learn new things that are difficult: if i don't get it right away I'm "stupid"... and I want to give up. But all that is is a conditioned response from the way we are educated. If I push through and learn something anyway, then I can replace those conditioned responses with new feelings about learning. Learning is a fundamental aspect of who we are as human beings... especially as ENTPs. Read things, get excited about things, think things through... and you'll feel fulfilled. The longer you do that outside of school, the more you will own your own learning. THAT is the feeling to replace your feelings of idiocy with.

Have goals, do things, train your focus. Do this despite how awful you feel about yourself and your abilities, despite how much you're going to fail at first. That's the only way through.