lumbar sacral spine pain and core exercise

I recently started exercising this week. I haven't done abdominal exercises since I was a teen. I'm 36. I did crunches mostly this week and some squats, etc. Also, was a stressful week with helping family and cleaning my house. I feel like I overdid things. I have lower back pain and soreness. I have to stretch my lower back and pelvis every half hour. Now, when I try to do even gentle core exercises like lower ab leg lifts or "dead bug" core exercises, I get a crack in my lumbar sacral area or a joint pulling, not sure. when I lower my leg. It is uncomfortable, and I can't do ab exercises right now. I did have an SI (sacroiliac) joint injury when I was a teen, too My main mission was to strengthen my core to strengthen my spine, as I might be starting with scoliosis. I am overweight too and most of my weight is at my middle, so I really need to strengthen my core. Should I wait and let it heal before trying exercises again? Are there specific exercises I should try? Should I seek out a specialist. I'm really worried about my spine right now. Any good nutrition for healing, too? Any advice would be great. Thanks so much, I very much appreciate it, truly. Forever grateful.