Burning the flag is not illegal. http://time.com/3907444/flag-supreme-court-history/

Burning the flag as a form of protest is not in any way protesting your loved ones' service. On the contrary, one could say the protest is happening on their behalf; it's crying out against a culture that no longer stands for what it claims to, for what many fought for it to be. The flag represents the nation, not any one person or their accomplishments. Desecrating it sends a strong message of unrest and protest against the state of the nation. Protest is intended to be controversial. If it was polite and gave respect even to people and concepts who don't deserve it, it wouldn't accomplish anything.

You should be less concerned over a piece of cloth, or even a symbol, and more concerned about the culture you are living in, the social and political climate, the rights of yourself and others - both civil rights in general, and more specifically the rights to life, liberty, and the pursuit of happiness - rights which many are having violated or revoked, or in some cases, haven't been given yet. Without the populace fighting back and protecting themselves and each other, without dissent, without protest, things are going to hell in a handbag right quick here.