It's about your expectations and needs.
The question you must always answer is "Can you feel happy BEFORE you have the actual manifestation"? Hopefully the answer to this is yes!
Close your eyes and start to feel what it will be like when whatever it is you want has come into your life. Feel the joy, the happiness, the ecstasy you'll be experiencing when it happens. Garner these feelings BEFORE you receive the manifestation. Remember that it's a three step process - Ask (you've already done that), Receive (the Universe has already created it and brought it to your door), Allow - this is the key - eliminating resistance and creating the vibration that will enable you to allow you to accept what you've asked for.
So many of us have resistance and so we don't get what we want and have asked for. And as typical humans we then blame it on the Law of Attraction, simply proclaiming that "The Law of Attraction doesn't work". At some point we need to take responsibility and realize that the Law of Attraction works but we have to go through the steps and "do" our own work.
We are vibrational beings and our primary moment by moment goal should be to raise our vibrations in an attempt to feel the joy that is our right. We can feel joy without having something in front of us.
Let me give you an example. Even if you are tired of hearing about my running experiences, they help you understand what I'm talking about. I am looking forward to the running trek across Tennessee in July. I've been aiming for this for almost a year now and whenever I start to feel "down" for some other reason, I always "go" there in my mind and it raises my vibration immediately. I feel happy. Do I have the experience yet? No, it's not July and I've never done this event before but I can feel how I will feel in the 10 day trip. My vibration skyrockets when I do this.
But that's not a physical manifestation, you say. True. As I was planning this post I realized that even though I have not manifested a car yet (because I haven't made up my mind as to which one I want - we've talked about that before), I get great joy and pleasure out of imagining each car at the time I think I want that kind of vehicle. My mind gets off any problems or troubles and I smile and think about sitting in and driving that particular vehicle and I am happy. This feeling can last as long as you'd like. You just have to continue thinking about the feelings you'll have.
In the health arena, imagine and then feel how you'll react and be inside when you get the clean bill of health and the doctor tells you everything is fine. Hold on to that happy feeling - like you're doing cartwheels. Or, if you want, envision how great you'll feel when you feel strong and able to run or lift weights or just make it through the day with tons of energy - whatever it is you are asking for.
Do NOT entertain any "Buts" - get off your "but" and if one comes into your thoughts, then immediately say "That is not my truth" and go right back to envisioning and feeling the joy associated with receiving that gift. Remember the 68 second process and try to hold onto that good vibration and excitement for at least 68 seconds - simply basking in the joy of receipt.
Try it, you'll like it and you'll realize you don't really need the manifestation in order to experience the happiness and other feelings that go along with the manifestation. Plus, you'll find yourself going to various "places" in your mind and emotions during the day just to feel better!
Let me know how it's going for you.