How to fix this weird zooming :(

Difficult to see how you are zooming in but you need to have the zoom focus on some geometry. That is probably why it suddenly jumps to what seems to be a void.

Actually, it’s not a void, the thing i’m building seems too small for the zoom. I don’t know How to make it zoom even if the thing i’m building is small. This happens also with parts of some objects that are big, when i zoom, they are cut …

Your model looks like part of a building. If so, are you not building it lifesize?

If for some reason you are modelling at a much smaller scale than lifesize, you may be encountering the problem SU has with very small things. In that case, you should use the Dave Method.

looks like clipping to me
search forum for similar issues, there are plenty
or help page there

My guess would be clipping as @paul.millet mentions, probably being caused by the ‘door’ component being downloaded from the warehouse and being well out of scale to the rest of the model.
Attaching the model would allow people to check it for you.

Tweaking the mouse’s smoothing feature solved my zoom on steroids issue.