gauges, head unit fuse blowing

Please read this carefully as there is clearly something very wrong and I am confused about how to fix it.

   SOooo, I turned on my car two days ago and heard the distinct sound of a fuse popping, lo and behold, my guages are dead, and so is my HU. My first though is that i had blown mutliple fuses, why else should my HU be effected by the guages, I find that in fact I only blew the guage fuse, I replace the fuse and everything seems to be fine, so I look at the wires, don't see any visible shorts, and go about my day. (At his point allow me to ask all you installers, does this mean that the person who installed my HU three years ago tapped into my guage circuit for 12+ constant, is this inappropriate? it seems like it is considering this is a 7.5 amp fuse, seems pretty small for an HU and the instrument panel?)<question 1>

   I get in the car at work turn the key and pop, same fuse blows. So now i am curious about why the ignition/starter is blowing the fuse. so, with the car running, I replaced the fuse, viola, everything jumps to life (guages and HU) and I am fine, Or so I thought. As I was driving I went over a bump( nothing crazy here, just like going over railroad tracks) and pop, fuse blows. Now i had the HU on and running, but since it was a physical event that so coinsided with the blowing of the fuse, i am pretty sure that there is a short in this circuit somewhere.

So i pull over, and put in another fuse. and..... everything works again. At this point I am confused. Whatever the problem is, it is acting like a short sometimes, and an overloaded circuit at others. It gets wierder.

This morning I get into my car, remove the guage fuse, as an experiment, and start the car. Car starts, with dead HU and Instrument panel, and I reinsert the fuse, it blows right away. I repeat this process with another fused, to make certain it wasn't a bad fuse, and pop. So now I know something is shorting, Right?

Why would this happen all of a sudden? <question 2>

how can I make sure it is a short or an overloaded circuit? <question 3>

Why would it have gotten worse? meaning, initially, I only blew the fuse with ignition, then it happened while driving, but seemed to be solved by a new fuse, and now no fuses stay intact. all this in three days. please help.

I've had short on the other side of the HU and the HU goes into short protect, so I know that this is on the power side of the HU, since the HU won't turn on. SO what are my options? 1) search for the short. 2) run new wires directly from my batt to a distro and make sure that whatever hack job was done on my HU/guage circuit can be corrected by isolating the HU.

sorry about the long post, and thanks for the help