How about a picture of the plant? Tell us what you did when you tried to hand-pollinate before? Were the flowers wide open when you did it? The flowers must both be mature enough to produce viable pollen, and to receive it. You said above "the flower buds came off from the wind" so if the flowers were still buds you couldn't have pollinated them. You need to look at the flowers with a magnifying glass when they are open all the way to see if there is pollen, and if it is ready - fluffy and dry - to just brush off with a tiny artist's paintbrush.
If you've only had this lemon tree for less than a year, you really should not be thinking about letting it make fruit anyway. You need to let it grow roots, and get established for at least a year before putting any of the plant's energy into making fruit for you.
You definitely should be fertilizing it with citrus food regularly. If the fert you have says "every 3 months" then where you are you would put fert on the plant in March and again in June I would think. Not now. Look ahead to the future when you will have grown a nice lusty little tree well grown in a big pot, THEN think about pollination and fruit production - maybe next summer.
