On one hand, being back at your old school could be a subconscious desire to return to a time when you were younger, and things were more simple. On the other hand, it could be a reminder to you about lessons learned from your younger years, and a 'warning' not to repeat the same mistakes.

Hair is highly valued by most cultures, and is a valuable dream symbol. It is symbol of vanity, security, sensuality, sexual appeal, and of youth. It represents physical and spiritual strength. In dreams, hair can represent our thoughts, knowledge, and reasoning.
Cutting your hair may symbolize a need for a more organized life, or 'less thinking'. Also a symbol for denial of sensual, and physical drives or urges.

Being ignored may reflect your feeling of being ignored by people in your daily life. It could also suggest that you have a low feeling of self-worth, or low self esteem.

I hope this gives you something to go on, good luck!