Welcome to home brewing. You've got 2 different issues you say. Over carbonation in your case is just not hitting the mark where you think it should be, but not gushing. You probably used just a marginal amount of too much sugar. This is very difficult to get just right as the difference between under-carbed, just right, and over-carbed is probably a half ounce or so. You then have to know exactly how much beer you have. It may look like 5 gallons, but is really 4.5, and then you only bottle 4.25, or some such variation. Just be glad it isn't gushing. As for taste, did you add the hops at the proper time in the boil. Flavor hops aren't boiled for more than a minute. The yeast should also add their own flavor when at the proper fermentation temp. Too high and you'll get esters, too low and you get nothing. I prefer the dry side of yeast myself. And one more thing, were the hops fresh? Old stale hops won't give much taste.