Avacado Tree HELP PLEASE!!!

[What did I do]

Just finished putting in a few trees in the backyard and they are all looking... decent with the exception of the Aacado tree.

Tree type: Lamb Hass
Planted: about 6 months ago

Additional info:
The tree was lush and green when I took it home from the nursary. Looked like it was a winner and was very happy with my selection. Ended up planting the tree about a week later. From this point the tree seemed to get weaker and weaker. I dug the hole about twice the size of the "root ball" and mixed in an assortment of mulch and topsoils (recommended to me from where I purchased the plant) along with a bit of citrus fertilizer. After the inital planting, I soaked the tree every other day for the next 2 weeks. At this point, things didn't look that bad (didn't have enough time). From this point, the sprinklers would water the tree twice a week for 15 mintes along with giving the tree a light soak every other day. The tree started taking a turn for the worse. At this point I spoke with a few people and they said that I was watering the tree too much. So, for the last month, I have just been letting the sprinklers do the watering. Well, the tree has (in my uneducated opinion) gotten significantly worse. I am open to any and all ideas that you might have. I should note that there are a few new "shoots" that are trying, but I am still very concerned.

I dont know how to insert photos into this thread, so I put them in "my album" which can be seen by clicking on my screen name.

Thank you in advance for any responses.

Mike