Problem with my car: 1st gear messed up?

Hey guys, I have a question about my first gear. I have the 08 access cab pre runner manual 5 speed. i can only put it into 1st gear when I am at a dead stop. If i try putting it into first guy like at 1-5 mph, it will not go in, there is some resistance that is restricting it from going in. is this normal?

instead when i am travelling at a speed about 1-5 mph, i just put it into 2nd gear because that's the only option available. when i do this, my car starts shaking/lugging, like I need more gas. is this normal? every time it shutters like this, i get scared, like i'm messing up my car or something.

so... my question is how do I fix my 1st gear so it can go in and is it good/normal to feel that shaky/luggy feeling? thank you all!

 

thanks!