This is actually really normal development at 15 months, where babies start asserting independence and exploring the world more on their own terms, which can feel like rejection but it really isn't. As a single mum it can sting more when you're her whole world, but her wanting to play alone and test boundaries is a healthy sign she feels secure enough with you to branch out, leh. Keep offering connection through play and cuddles when she's open to it, and stay consistent with gentle limits when she pushes back.