Can't figure out why my Cedar Elm tree is dying...

I have been watering this tree about three times a week ever since it has gotten very hot here in Texas (90+ days for about month now).

I noticed a lot of leaves are yellowing... and my lawn is filled with fallen yellow elm leaves.

I noticed there is clear sticky sap coming out of the bark in some spots.

Any advice would be greatly appreciated to help save my tree.

Please click link below to see some pictures.

http://goo.gl/ectYB3

Can't figure out why my Cedar Elm tree is dying...