Thoughts on water...

So last night my buddy and I brewed our first All-Grain recipe. A nice Irish Stout thats looking at about 4% or so. Everything went great! Here is the issue that we may have or may not have...I would like to get your thoughts.
So when I went to the store I accidently picked up the wrong water...I got distilled water...we used it anyways but thought to add about 1/2tsp of gypsum into our water that we used in our mash process. Color was great, things checked out fine testing with iodine. From there once we started boiling we added another 1/2tsp. of gypsum hoping this would help since we used distilled. Once the boil was done and after using our wort chiller we put into the primary we added cold filtered tap water thinking this may help as well which brought us up to 5gall. Got to our temp. pitched our yeast and hoped for the best. What do you guys think? Will it turn out okay or were we doomed from the start. Thanks guys, appreciate it.

It might be a little tarter and acidic than desired, due to the lack of alkalinity in that water. But it should come out otherwise fine. You properly added a dose of calcium salt into the wort. I don't know what that amount of gypsum equates to with regard to calcium concentration, but it will be better than if you hadn't added it.

Not doomed, RDWHAHB

It doesn't matter much what you do to water after dough in - the mineral content at that point has an influence on mash pH which is arguably most of the story as if you get that right other things tend to fall into place.

A nominal Irish stout (i.e. one following Lewis's (Ashton) recipe in Lewis's (Michael) monograph in the AHA series) will come in at a mash pH of 5.5 - 5.6 using low calcium water. Your addition would be enough to bring it down to approximately 5.4-5.5 which is just about spot on. This of course makes several assumptions. Unusually high (low) acidity in the roast barley and/or base malt would result in a lower (higher) mash pH. But I think you are pretty solid - statistically speaking.

It would be much better if you knew what the actual mash pH is. Buy a pH meter.

Wow thanks guys. I appreciate the comments. This helps a lot.