16 kilos in 16 weeks is a massive amount - i would set yourself a bit longer to do it. i lost 4 stone in 4 months which i still feel was too quick, was too much of a shock for the body.
why have you become a veggie? i think you really need to know your stuff if you want to lose weight effectively as a veggie because you will miss out on so many vital nutrients. my mum was veggie for 25 years and now eats meat as she realised it pushed her into early menopause and was in a poor state of health as a result. im not saying dont do it but REALLY have your reasons and know your stuff!
apart from that its hard to give some advice without knowing more, there is lots of information here, theres a link through my profile to lots of information etc. again more info is required!