If my husband left me the other day, is it legal for him to go and take everything just because he is upset?

Unfortunately, he can drain the bank account as long as his name is on the account and there is not a court order that says he cannot.  However, he is incorrect in saying that it is his money alone because he was the one working.  Any wages earned during the marriage are considered community property in Texas, as such you have just as much right and access to the funds.  If he hasn't scooped everything from savings/checking/ or the piggy bank-- then get together what you can and use it open up a checking account in your name only to restrict his access.

If he has already scooped everything out of the accounts, then you do what you can with what you have left.  If you have anything worth pawning, it is within your right to raise the funds you need to care for you and the children.  You also need to get with a legal aid organization to get a divorce going and file a motion for temporary orders.  Depending on your history you may qualify for marital support in addition to child support.  You can also ask the court to order him to return part of the funds that he took off with.  The district clerk in each county usually knows how to get in touch with the legal aid group for that area.  If you have any funds available, you may want to consider hiring an attorney-- if you can to get things moving just a bit quicker than the legal aid organization.  Many family law attorney's now accept payment plans which makes retaining an attorney easier than it used to be to hire an attorney.

It's hard to think divorce when you have no money and 2 kids to take care of.  Your third step should be contacting as many non-profit organizations or churches as possible to help you get back on your feet.  You can also contact the kids schools to see if they qualify for free or reduced lunches.  There are also several websites that actually specialize on living and entertaining kids on a reduced budget, like mommysavers.com.  When you visit with the legal aid group, they may also have a list of local organizations that can help with groceries, utilities, and rent.  It won't be easy, but the important thing is to keep focused on what's right for you and kids.  The rest will eventually work itself out.