Not understanding how someone has so many problems

My girlfriend and I are perfect for each other. We felt a spark from the beginning and instantly fell in love. We live together, and that has never caused any issues because we communicate so well. I am already looking at engagement rings after a year, and definitely plan to marry her with no hesitation. We both have struggles with very similar anxiety and depression, which has greatly helped our connection because we understand each other much better when we are feeling down. From the start of our relationship, we agreed that we both felt as though if we're facing any sort of problems, it's always best to talk about it (whether it's between us or personal issues) in order to avoid repressed feelings, arguments, or any sort of issue that could be brought up in the future. This has worked out greatly with keeping open communication throughout our relationship, and has prevented almost every argument from turning into anything more than a discussion. But it has put me in a difficult situation. I very rarely complain about problems. If I do complain, I usually just state what I'm going through, and leave it at that to avoid keeping things to myself but don't let it linger. But for about the past 7 months, my girlfriend has been complaining every single day and it just doesn't seem to stop. What she complains about ranges from very minor to very serious things. Once one problem is resolved, the next day there is sure to be something new that's causing her stress and anxiety, whether it's physical pain, problems with work or family, general depression, and so on. I have had the feeling she was being a little over dramatic in some situations, but have never said so because even if the problem isn't as bad as she makes it out to be, her anxiety could genuinely be making it feel much worse and much more real to her. I am a very patient person, and have always been as supportive and loving as I could possibly be. When I am going through something serious enough to affect my day, she is very supportive and helpful, but once I stop venting or complaining about my problems and feel better, it always goes right back to hers either the same day or the next. The dilemma I face is that I feel as though you can't tell someone that they have too many problems or that they need to complain less. Besides the fact that it just feels mean and inconsiderate, I think if I tell her that, she would feel the need to repress her feelings which would end up causing more problems in the long run between us. She has realized that there have been a few times that she has lashed out, and has been making a big effort to stop that behavior and made lots of positive changes. But that still doesn't stop the fact that there's always something, big or small, that's causing negative emotions that she feels the need to express. It has caused me lots of emotional exhaustion, and feeling a lack of support because I always have to be helping her. I have considered keeping a journal of her day to day complaints so that if this ever does get brought up, I would be able to show her that I'm not exaggerating. But that goes back to contradicting us agreeing that we need to bring up problems with each other as they arise. I'm just not sure what to say or do anymore and it's testing my patience, and in some cases causing me to take her problems less seriously than she thinks I should be.

Hi Redwood, I don't mean to be rude here, but it kinda sounds like your girlfriend is seriously self-absorbed and a downer to be around, but, you want to marry her, so....I suggest a little gentle expression of irritation, ie; when she's on her third petty issue for the day, just say to her, in a mildly irritated tone, "What are you bitching about now?", with the emphasis on 'now'. Either that or sit her down and explain that she seems to be moaning about a lot of petty issues and you're wondering if she's happy in the relationship. You have a 'clear-the-air' policy in your relationship, you don't have a 'dump-your-petty-crap-on-me' policy. Set her straight, she's either happy or unhappy, if she's unhappy......there's the door.