Shibariya Komachi

Summary from Aerandria Scans:

Chiko is a high school student who can see other people€™s red threads, or the thread that connects one person to his or her soulmate. She uses her ability as a musubi-ya to advice schoolmates on their lovelives, for a fee of course! But upon stumbling upon a hidden room at her school, she sees a mysterious looking white spool of thread that suddenly comes alive and traps her. The next thing she knew, her body has become like a ten-year old kid again and the only way to get back her body is to use the mysterious thread to expel evil spirits and become a real musubi-ya!

Creator: TAKEUCHI Mick
Status: Ongoing
Genre: Fantasy, Romance, Shoujo