Ask an arborist

You said, "... the leaves were turing yellow and also the new leaves were also turing yellow . does that mean that i gave it too much water...". I don't know how much water you gave it, the age or the size of your tree or where in the world you live. I suspect you are in the US even though this site is in the UK.

You also said, "...or that ther is a bug eating it the trunk looks fine...". Do you see any evidence of bugs or holes in the trunk or branches?

You said, "...i also have a bush near by wwith the same yellowing...". And the name of the bush is? Did this get watered too? What has the weather been like where you are? Are you in a drought, lots of rain, any herbicides used nearby?

There is something called chlorosis that causes yellowing of leaves. Different deficiencies will cause the yellowing in different ways. Take a look here to see if any of these patterns fit. With these longer links you may have to copy and paste as they don't always post to be clickable.
http://www.urbanext.uiuc.edu/focus/chlorosis.html
http://plantclinic.cornell.edu/FactSheets/microchlorosis/microchlorosis.htm

You can also contact your local extension service if you are in the US. They can also do a soil test for nutrient deficiencies at a reasonable cost.
http://www.ceinfo.unh.edu/cesites.htm