13 is an awkward age. She's just beginning to be aware that there are differences in situations and circumstances, and she'll hate that. 13 is an age where you don't want to be different to your friends, being the same = acceptance, being different = the possibility of rejection or ridicule.
At 13 our middle girl decided that only designer brand clothing was good enough because that's what her friends were wearing, and she knew they were expensive and to her it was simple. If we loved her we'd lavish money on her, whether we had it or not. I only once bowed to pressure and bought her some expensive leggings, which she and her friends promptly cut the legs off to turn into shorts because the leggings were "too hot". Of course then they were too short so she never wore them as shorts either. I was livid, and we had a free and frank discussion about it.
At 13 she is old enough to begin to understand the realities of life. Yes you'd love to be able to move to a bigger house where she could have her own room; but you can't. As other's have said, it is what it is. You are doing your best to give her what privacy you can, and she just has to accept that.
Without going into information overload, use this an an opportunity to talk about the cost of living - house, food, etc -vs- available cash, and the fact that everyone has to budget, and introduce the reality of what it means to budget (she'll need to learn that lesson at some point anyway so may as well start now).
Bottom line, of course she's being ungrateful, because she's 13 and at the moment can only see things in terms of how they affect her. That's totally normal for her age group. We only learn gratitude as we get older and realise that whilst we don't always have what we want, there is always someone else worse off. Don't stress about it, don't take it personally or allow yourself to be upset by it. Your'e doing fine 