Sorry about troubles. Here are some ideas:

"When I bend forward to touch my toes there is a small crack in my lower back (no pain, it just feels weird when it happens)" - No way anyone with sciatica can do that. This is gluteal and perhaps piriformis with maybe some sacroiliac with it. Some techniques:
1) Stretch- Sit; Cross affected leg over knee. Lean forward while maybe pulling up crossed knee. - If it's piriformis you should feel the stretch.
2) Positional release: - Lie on stomach in bed and drop affected side over edge of bed holding in about 90 degrees and try to pull it in a bit (adduct). Nice to have a stool the right height to hold knee. If you get the knee in right place piriformis will relax and if you hold it for 90 seconds might be good a few hours (help you sleep).
3) Flexor-extensor reflex - If you pull up the medial muscles above the knee while touching your prirformis buttock area in about 30 seconds the piriformis will temporarily relax.
4) The best measure ( besides botulinum) for piriformis and gluteal muscles if a repeated robust brutal transverse stretch/massage:
Piriformis Syndrome: Diagnosis, Treatment, and Outcome—a 10-Year Study
Loren M. Fishman, MD, George W. Dombi, PhD, Christopher Michaelsen, MD, Stephen Ringel, MD, Jacob Rozbruch, MD, Bernard Rosner, PhD, Cheryl Weber, MD
Arch Phys Med Rehabil Vol 83, March 2002 Pages 295-301
https://www.archives-pmr.org/action/...2802%2909009-3

I start by having bad side up lying on side and engage muscles of buttock with fingers above tender muscles towards foot with finger - pushing down for 10 minutes and then pulling up with fingers from below for 5 minutes and then knuckling area. Do tender locations 2-3 times a week. Can really hurt to start but benefits are obvious. I do both gluteal and piriformis muscles that way. Can take weeks to get substantial results. Haven't been able to find a therapist mean enough to do it here so I (an MD) have to do it...
I discussed it here:
How Should One Investigate Chronic Back Pain and What about the Back Muscles? | Pain Medical Musing