My eyelashes used to be very long, thick, and even. I have a nervous habit where when I put on mascara (and I put it on pretty thick), I always end up picking it all off, and the result of this is many of my lashes have been pulled out. It's gotten so bad that the inner part of my eyes are almost completely missing their eyelashes. My lashes are not as long and beautiful as before, and I am distraught because of it. I cannot stop this nervous habit though, and I'm worried that my eyelashes will never grow back to their full length now that they've been pulled out. Do you have any idea if they ever will, or any suggestions on what to do?

This may be because of the mascara kind your using..
And I think waterproof mascara specially do make the eyelaches falls down (from my personal experience)

And eyelaches are normal hair they will grow back for sure but you have to take care of them..

I think you should stop putting on mascara for a little while.. let them grow back again.

This treatment requires a doctor's prescription, but will not prevent
Your habit of pulling your lashes out:

LATISSE™ Home | LATISSE™ — the first and only FDA-approved eyelash growth treatment

I have the same problem as you! Everyone used to ask me about my eyelashes and how I get them to be so long. But I get bored and pull off my mascara. But now for some reason, some of them are growing straight! And they bend at the end and point to the ground... god.

If you observe that your eyelashes are start to fall out it is important to avoid panicking. Often times a bit of eyelash loss can be natural, as weak lashes fall out and are quickly replaced by new, healthier lashes. Keep a close eye on your eyelashes for regrowth, and when your eyelashes are significantly growing back then you probably do not have anything to worry about.