Hi mum, I had something quite similar during pregnancy also and that “loose” feeling can sometimes happen because the pregnancy hormones relax your ligaments, so the pelvis and hip joints feel less stable. Since you already feel like the leg might give way, I would be a bit careful with too much walking for now and avoid sudden movements or standing on one leg too long. What helped me was gentle pelvic stability exercises like slow side leg raises while holding onto support, and also sitting exercises instead of weight bearing ones when the pain is bad. But honestly, since you already feel like you might fall, I would really suggest seeing a physiotherapist or gynae for assessment because they can give you more targeted pregnancy-safe exercises.