Eyelashes falling out

My eyelashes have started falling out in bulk every few months. It all began after trying an eyelash grown serum. It worked really well, my lashes grew SO long and curled more upwards on their own and were thicker. Then they started to fall out a few months after. I tried a different serum that worked but then the same thing happened. And again. And again. And AGAIN. So I switched to castor oil nightly after giving my lashes a few months of nothing on them at all. The castor oil made the pretty long but didn't really make them as thick and curly as the serums. But they just started falling out AGAIN!!! My natural lashes are really straight and short and when they were thick long and curly I gained so much confidence, but then I lose it double time every time half of them decide to fall out all at once. I'm not rough when washing my face / eyelids. Any ideas what I should do going forward? Any products I can still use to try and grow them long and full and curly without them falling out within months??