<human>: Ok so my girlfriend (F29) of 8 months finally told me (M26) what had been bugging her lately. (we have been keeping communication really low over the last week).

She told me that every couple of months she seems to go from being madly in love with me, to the point where she needs me 24/7; to having no feelings for me. And it keeps happening to her. Back and forth. I've noticed she had been silent at times before so when it happened this time I asked her about it and finally got her to talk.

She tells me I don't do anything wrong at all, but she doesn't think she should be feeling this way (the back and forth feelings).

I know that this is the most serious relationship she has ever been in, as she has told me this so many times. It has also been the most serious one I have been in. 10 years ago she had a serious issue with depression and just last week started to deal very minor health problem.  very minor but it is bothering her.  Now she is constantly stressed out about everything going on in her life (work, family ect)

Is this normal? 
What should I tell her or say to her? If anything.

Last message I sent her a hour ago, I said that I love her more than anything and we would figure it out together.

Thanks for any advice Reddit!

Provide a brief overview of the text.
<bot>: Very serious relationship, girlfriend keeps having emotional shifts, might be related to stress or depression.  Not sure what to say or do.