Clinique Happy is quite a bit sweeter than TdH, there's no lemon to be found in it. It also doesn't have quite the weight that TdH has. Personally I like Happy more than TdH but I think TdH just doesn't do well on my skin.
May want to try Calvin Klein Euphoria, I usually wear it and Happy at the same time as I feel they complement each other and make a scent greater than the sum of it's parts.
EDIT: Lemon is in fact listed as one of the notes on Happy, but I'd call it "lemonade" and not lemon.