If you go onto Coeliac UK they've got a brilliant site for questions you might have. When I had my blood test results I found looking on there very informative.
It is invasive but only for a short time. You're awake during the procedure and it really is for your health benefit. Again the website would be able to answer this better than I can, I think.
I personally had awful symptoms before the blood test. Lethargy, bloating, horrendous toilet escapades, depression... awful. I didn't get to the invasive part (various reasons) but I changed to a GF diet and I dont get the aforementioned symptoms at all now.
I promise you it's not so bad. Daunting at first bit you adapt easily. A lot of places cater for GF. Loads of supermarkets have a whole GF range. Plus there's a whole bunch of restaurants - Bella Italia do GF pizzas and pasta dishes. As do Pizza Express. Dominos do GF pizzas. Subway, Maccys and Burger King you have to either have a salad or take out the bap/bun. Smaller restaurants will usually have something on their menu that is gluten free too.
Once you get used to reading the ingredient labels, you're all set. Most of the allergens are in bold now so your eye goes straight to them. And failing that they usually have a section that says allergens: nuts/eggs/milk/gluten etc.
There are some that say made on a factory that handles gluten or something similar. It really depends on your sensitivity or whether you want to risk it. I'm not too sensitive so I can get away with those mostly.
Drinks - be aware of these too. Hot chocolate and shop brand coca cola/diet coca cola Are terrible.for adding cereal to thicken them or barley malt (for flavour/colour?)
Oh and one more thing... don't buy into all of the GF ranges. You'll find particularly with things like pasta sauces, or things other than pasta and bread, that the 'normal' stuff is fine. For instance, Dolmio sauce doesn't have any gluten in it. If you buy the sauce from the GF ranges though, you'll end up paying twice the price, sometimes more. It's a bit of a con and unfair on those who don't know quite how to navigate it yet (but I guess that's business?)
Like I say, once you know how to navigate it all, you're set 