a head gasket cannot be "loose". It can be "blown" or "leaking" but it cannot be "loose". It is trapped between two substantial chunks of metal (the head, and the cylinder block) that are held together with 10 very large bolts.
Right now, this situation could be anywhere between:
1. You are not explaining the situation properly and are mis-quoting and/or misunderstanding what you have been told, or someone is telling you something incorrect (possibly based on wrong or poorly-explained information), and there is actually not much wrong with the bike because the slight coolant leak that was the real original situation did not leak out enough coolant to actually let the engine run dry.
2. You are not explaining the situation properly and are mis-quoting and/or misunderstanding what you have been told, or someone is telling you something incorrect (possibly based on wrong or poorly-explained information), and the engine is completely lunched - it is now a lump of scrap metal - due to having been run without coolant at all for 20 minutes.
There is only one way you are going to find out the truth. Get the bike to someplace competent, and get them to properly diagnose what's wrong.
Don't jump to conclusions and don't try to diagnose it yourself - you will be wrong, you don't have enough experience to properly explain and understand. If you try to diagnose it over the internet, it will be based on incomplete or incorrect information (for the same underlying reason - you don't have enough experience to properly explain and understand) and will also be wrong. Garbage in, garbage out.
Known trustworthy local shops that i have personal experience with are pro 6 cycle and z1 cycletech. I would not give this to rosey toes. It's not that i have anything against that shop, but engine work on modern sport bikes are not their specialty. Pro 6 and z1 cycletech are roadracing shops that have a ton of experience with that type of bike.
If the collective suspicions of this forum are correct (in that you have lunched your engine by running it for 20 minutes without coolant, and it now won't start because it doesn't have any compression because either the head is cracked or the pistons and cylinders are all scored up and the rings are shot) it is going to cost a lot more than $1000 to pay someone else to straighten it out - this means buying another engine and paying shop labour rate to remove your engine and install the other one. You don't have the experience to do this yourself successfully ... I know this, because if you did, you wouldn't be asking the questions that you are asking, in the place that you are asking them!
Tough talking? Sure. Hard lesson? Absolutely. When all sorts of red warning lamps come on, or gauges on your instruments go out of bounds into the red zones, or fluid leaks out of your vehicle, stop. Immediately. Shut the engine down and don't drive any further until you fix the problem properly. The tow will be less expensive than the repairs afterwards.
By the way, that generation of r1 engine is pretty near bulletproof ... But they won't survive running without essential fluids like coolant or engine oil.