Are you looking to boost your metabolism or are you looking to increase your energy? Two different things.
As far as boosting your metabolism - the rate at which we burn calories - the only proven method is to gain MUSCLE. The more muscle we have, the more calories we burn just standing still. I'm not sure what you mean though when you say that your "metabolism" isn't high enough. Everyone's metabolism is different - it is what it is. And that won't effect how you FEEL.
If you're sluggish and tired - that's another thing entirely.
The best way IMO to energize yourself, to be productive and peppy and full of vitality is to get down to a healthy weight. You will be AMAZED at what this will do for you. AMAZED. And luckily it doesn't take getting all the way down to goal to start seeing the benefits.
I'm fairly certain that within a short amount of time you will start feeling better if you eat a HEALTHY diet - adhering to a calorie allotment full of fruits, veggies, low fat proteins, whole grains -
eliminate the added sugars, refined carbs, fatty foods. Discover how you should REALLY be feeling and hang on tight - because you won't believe the difference. Your energy level will soar.