I wear braces & while playing basketball i bumped into another player & my front tooth was hit. bracket is ok but the tooth feels loose. advice?

See your dentist: See your dentist immediately for an x-ray to determine if permanent damage has been done. Otherwise, your braced will stabilize your tooth until it heals.

Wait several days: During orthodontic movement the teeth are under stress and the periodontal ligament connection to the bone is at its least stable. Trauma will magnify this instability leading to a "loose" tooth. If the damage is reversible your tooth should "firm" up in a couple of days and there should be little or no lingering pain. If you have increasing pain and swelling then go see a dentist asap.

Call orthodontist: Call your orthodontist immediately to inform them about the incident. Be certain to tell them about the mobility and any other damage or pain. They will likely get you in soon to check for loose brackets, inspect the arch-wire for deformation - if deformed could displace one or more teeth, test for mobility, and possibly x-ray the area to check for potential crown/root/alveolar bone fracture.