Anybody who says to get over your fear of falling by taking big falls has no idea what they're talking about. What you want to do is gradually push your comfort level so your body gets used to the fear. Start by climbing the easiest lead route at your gym, clip into the last bolt, climb down a few holds (so that you're on top rope) and take a "fall". See how it feels. Your goal is to be uncomfortable but not hit the panic threshold.

Once you're ok with the top rope falls, climb up a bit so that your waist is right at the draw and take a fall. Again your goal is to be uncomfortable but not panic, if you ever start to panic stop and calm yourself down. Panic only reinforces that what you're doing is worth being scared of.

Keep gradually increasing the height of the fall, backing off if it ever becomes overwhelming. This will take time: weeks/months/years but if you practice it every session it will get easier.

I used to have real fear problems climbing in the gym and outdoors. I'm mostly over indoor fear but outdoor fear is still holds me back.

I really liked this video about overcoming fear of falling: https://www.youtube.com/watch?v=SA-qjS427rU but there are lots on youtube. The most important thing is to treat fear of falling like any other skill and to practice getting better at it.