Anyway I can make my aircraft work better

I looked at your craft and I only had to tweak your craft a bit to get it flying well, you made a pretty good craft! Here are the things I recommend you change:

• The CoM is too far aft (and too near the CoL), you can set the 2 rear-most tanks to empty to move it forward, this will take care of the controllability issues.
• Increase the length of the forward landing gear, that way you have a positive angle of attack during the take-off roll which will help your craft take off before the end of the runway.
• Up to you, but I would consider adding a rotator to the horizontal stabilizers and set it to a slider so you can trim the pitch. This will help you if you don't want to increase the forward landing hear length, by trimming the hoz. stab for take-off you won't need to do that. An added bonus is that you can trim the pitch during cruise so you can have hands-off flying or pretty near hands-off.

The last point is more of an optional recommendation, but if you follow the first two then you can take care of your original problems.

Move the wings back?