First floor of house wobbles!
You are probably quite far from over-specified, if you have significant deflection from walking around. Such are the breaks of self-taught structural engineering, particularly if you don't use the resources of formal structural engineering in your self-teaching.

That which will stand up, and that which will stand up without unacceptable deflection from loading are different things. How this structure behaves in the face of various external loads should also be a concern; you refer to it as a house, and when houses collapse (say, in hurricane force winds) people get hurt or die.

Steel-framed floors are almost always built with a truss structure which has considerable depth, to provide stiffness to the structure. You appear to have a single layer of square tubes.

I would strongly suggest a consultation with a (licensed, professional) structural engineer.