Hello I have a Meyer lemon. It got full of blooms
and most turn into tiny lemons. Most of the lemons
fell off and a few stayed and started growing. They
are now the size if a grape, but the have all started
to turn yellow and have started to fall off. Does anyone
know why this would be happening?

Is this a young tree producing it first crop? - Millet (987-)

No, it's about 4 years old and this is it's second year giving fruits. As a matter of fact, it's an everbearing and it has about 8 lemons already that have been on the tree for about 5 months and are getting bigger. The ones that formed from the lastest bloom are the ones that are turning yellow and falling.

From my years of growing valley lemons , the spring flowering and fruit
setting is always poor in developing fruits for some reason. The rest of the year it always bears good crops.
So don't worry the next time it flowers it will get a Bigger crop