OK, so the short answer is, stay off the tooth as much as you can, and head to a dentist ASAP for radiographs and clinical exam.
"Loose" could mean a number of things, ranging from cusp fractures to root fractures, cracking and anything in between.
Subsequent dislodging and/or aspirating the tooth also possible...
If you bit your tongue, cheek or lip, salt water rinses (especially after meals) will keep things nice and clean so as to begin healing.
Hope this helps for now.
Konstantine Sayaf DMD (All Smiles Dental Ctr)