The list of vegetarian protein sources is endless.
http://www.veganhealth.org/articles/protein
Bread, pasta, cereal, rice, beans, peas, lentils, nuts, seeds, fruits and veggies can easily offer everything that you need except B12.
http://www.veganhealth.org/sh
http://www.pcrm.org/health/veginfo
All vegetarians should take a B12 supplement regularly since most people eat meat, dairy AND fortified cereals yet still have a B12 status that is lower than recommended.
http://www.veganhealth.org/articles/b12
It may help you if you see proof that vegetarians have the same potential as anyone else.
http://sports.espn.go.com/espn/page2/story?page=keri/080616
http://www.veganbodybuilding.com/phpBB2/viewtopic.php?t=13139&highlight=avi
http://www.veganbodybuilding.com/phpBB2/viewtopic.php?t=6610
http://www.macdanzig.net/bio.php
http://www.scottjurek.com/career.php
If you need meat or dairy during any stage of your life or to live any certain lifestyle, why does the American Dietetic Association say otherwise?
http://www.eatright.org/cps/rde/xchg/ada/hs.xsl/advocacy_933_ENU_HTML.htm