My bones crack upon movement...why and what can I do about it?

My bones always tend to crack upon movement, and sometimes it really hurts. I also have joint pain often. I'm worried this might be the beginning of osteoporosis, even though I'm only 19. (I have had eds... both anorexia and bulimia for the past 7 years, currently semi-recovered (I've gained weight and I'm at a "healthy" weight now, though I still continue disordered eating habits and recently fell back into purging regularly as I'm trying to lose weight again) Is there anything I can do to help the cracking? (I don't consume any dairy products and follow a vegan diet) Thanks in advance.

Take calcium and vitamin D supplements.
Go for a bone scan. You may be in the early stages of osteoporosis.
Get lots of weight-bearing exercising (walking, running etc) to keep your bones strong.

If you don't have your period that could be causing you to lose bone density. You may need to go on the pill to keep your hormones at the right level. This can stop you from losing calcium from your bones.

Osteo problems are really bad. Please get it checked out.

You can reverse the damage if you work at it.

Make sure you get enough calcium and vitamin D. Take a supplement if you need to. Make an appointment with an orthopedic physician to see if you have osteoporosis or something else.

You may have the early stages of osteoarthritis.
You can go to a rheumatologist quest a bone scan,
and they can tell you what to do from there.
Anti-inflammatory meds might help you.
Good luck!
:-)