First 5 gallon kit - I think I screwed it up

Ok, so this is what’s going on. I’ve read several books on brewing ( John Palmer, William Moore, Charlie Papazian, Homebrewing for Dummies ) but I’ve never actually brewed. I received a Northern Brewer Caribou Slobber kit for Christmas and did my boil 10 days ago. I steeped my specialty grain at 160 for 30 minutes in 2.5 gallons of tap water ( I squeezed the bag, Oops ) and added another gallon of tap water for the boil. Everything went well and I was able to cool the brew pot in about 20 minutes in the kitchen sink after the hour boil. After pouring the wort in the primary I discovered that I had accidentally purchased Distilled water instead of regular bottled water. Because I needed to add 2.5 gallons to bring me up to 5 gallons total, I knew that much Distilled water wouldn’t be good. So, I used 2.5 gallons of water straight from the tap. I didn’t think another hour spent boiling the water then cooling it was necessary so I just poured it right in with the wort. I used the supplied Dry Danstar Windsor Ale Yeast, which I re-hydrated in 80 - 85 degree Boiled water an hour or so before pitching. I kept the primary fermenter at 64 - 66 ambient temperatures and the stick on thermometer always read 68 - 70. There was vigorous fermentation for 24 hours, then, nothing much. Maybe 1 airlock burp per minute. My feeling is there should have been at least another 24 hours of vigorous action. My O.G. before pitching the yeast read 1.048 which is low for Slobber. The wort temp was a little warmer than 60, probably closer to 70. My hydrometer reads 1.004 in 60 degree Tap water. I’m not sure if all that brings me closer to the expected 1.052 for Slobber or further from it. After 1 week I transferred to secondary. The beer smelled like Whiskey, but good, and the taste was VERY bitter. The gravity read 1.022 at 68 - 70 degrees. I’m planning on leaving it in secondary for a month and leaving it in the bottles for 2 weeks after that before drinking. For all you experienced brewers out there, did I royally screw this one up or do I need to relax and let it do its thing ? If I did screw up, is there anything I can do to salvage this batch ?

Relax. You made beer.

RDWHAHB, yep you made beer. the low OG was probably due to the wort not being mixed fully after adding the water. as for your tap water, if you can drink it you can add it to the fermentor but if you don’t like the taste or have other problems with the water then i would use RO water

Thanks fellas, that makes me feel A LOT better !!! Roll Tide.