Newly planted Lilac not looking good (photos)

[slick-rides]

Bought this Lilac at a nursery and planted 2 weeks ago. Dug the hole about 2.5 times bigger than the pot it came in. Mixed in some bagged "raised garden bed" soil I had. We've been in a drought so it's been watered about every other day for about 10min. Thinking this might be too much water? Is that what's causing the leaves to have dried up brown spots and some others looking light green, not healthy?