Melody Improvisation n my suckiness

K I have learnt scales and there are 5 on the guitar. After months of struggling and trying to wrap my mind around sone music theory, I know some. But it's not enough for me to be able to improvise a melody out of the blue at a whim.

I don't know how to compose a tune, vary the rhythm, add fill-in and effect. Anything I tried playing sounds like just simple kiddish attempts or sound like playing scales. It's frustrating when I seem to be the only one in the class with problems... It doesn't help that I don't have any tune in my head to 'try to play out' on the guitar...

I do have to make an effort despite real difficulties. Nothing original comes to mind nor do I have a song I listened and like in my head... I picked up the electric guitar today, practice the scales cos if can't press the notes correctly, can't even play a simple melody correctly. So after that moved to trying to practice the known song's solo introd. After that I tried coming up with melody improvisation... Let's just say it's still kiddish n unoriginal. Don't know how to create a nice sounding tune. Not helping that I don't have ideas either through songs I've heard. Even Quetzal's helpful input, does not mean I can come up with something melodic.

Then there's the issue of moving and playing the tune across at least 2 scales, at least one note goes into the next scale to sound nicer... Bad enough to create a melody in a scale. How do you go about with 2, at least...

Sighs it's kinda VERY frustrating. It's still a big question mark and my mind can't seem to wrap around it. Guess I better make myself practice more and keep trying... I do find I can remember a few songs learnt from memory without having to refer to the paper. Last time can't remember even one. At least some aspects improving from before.

The remaining free-er days, I should practice daily to make sense of this 'melody improvisation' concept. Don't want to keep on sucking at it!

What is missing is the focus and diligence to keep practicing until 'Eureka' and suddenly my mind can comprehend this vague thing called Music.