Thank you all for the support and replies.
Don't worry too much about the posters who feel they need to tell me something they don't think I already know. I am an idiot. I have lent money to brother in the past, and he has burned me. I had shut him off for years. Everytime he would call, the first thing I would say once I heard his voice is "I have no money." It was no, plain and simple. He called in November looking to be bailed out of jail. I knew nobody else in the family could do it. I could, but I didn't. Jail would be good for him.
I have not "enabled" him in years. Others have, but not me. Why did I write this check out? Because I thought he was changing. He was coming back here, he wanted to be with the family again. HA. The ONLY reason I wrote the check out was he ASSURED me he had the money back in CA. He sold his bedroom set. He was going back to pack and get the money for his bedroom set. This was not a "hey I'll catch up with you on payday." I even grilled him on how trustworthy this "friend" was who was buying the furniture. He assured me the guy would have the money and he would send it to me for Friday.
As for my OP saying I can't pay my mortgage, maybe I should of but quotation marks around it. As far as my brother is concerned, I CAN'T pay my mortgage. He has no idea I have enough money to cover my mortgage. That is what is so hurtful. All he knows is that money is for my mortgage, and he stiffed me. It is a real eye opener. I had him shut off for years, this would of been a perfect opportunity for him to show me he has changed, and all he did was prove to me I can NEVER trust him. He is not just a jerk, he is a criminal. If you knew the amounts of money he owes various family members, it would astound you. Agian, you are probably saying "and...?" Sure it is my fault I lent him the money on good faith and got screwed. I am not denying that. I just wanted to come here and vent. I'll take my 30 whacks, thanks.
ETA: Just to be clear, the check was never written as a loan. The landlord allowed me to post date it a week, to give my brother the opportunity to get the funds to me, so I could put it in my account. The $950 was never intended to come out of my money. I took a huge risk writing that check. But I would not call it a loan. I guess it would be called a "float"?