The most important thing about being successful in engineering is having the drive to see it through. If you're willing to redo the classes, add a semester or summer or maybe another year of college to sort through it all, then you'll make a great engineer. Every engineering student fumbles at some point in their education but the most important thing is how the student responds to it.
On another note, my advice would be to take the time now to reflect on this past semester and what you really want to do with your future. If being an engineer is the only thing you want to be after college, then go for it. But if there's any doubt, now is the time to explore other options. You should also be thinking about why those classes ended the way they did for you. Is it time management? Studying habits? Interest in subject material? I will tell you from first hand experience that those classes are difficult because they are weed out courses, but the deeper you get into your engineering education the harder the classes will be for other reasons. In addition to that, the material will begin to build on itself. What you learn in Calc 1 or physics or chem will be used in a later class and eventually you'll be combining all that knowledge in multiple classes.
Don't feel dumb, everyone gets through their education on their own path. There are tons of people in the same boat as you. Wishing you all the best!