When life is great she wants to be married, no so great, she isn't ready...what's up?

Me and my girlfriend have been together for about two years and have always had a carefree loving relationship that is until things went sour and she lost her job. I stood beside her, took on most of the bills and never complained but she told me that she felt like for some reason if we weren't together that she wouldn't be going thru any of that and even said she felt like leaving me...very blunt and uncaring of how it might have made me feel. This was after we went to the jewelry store together and put a ring on layaway. After it all blew over and we got thru it she wanted to know why I hadn't asked her to marry me yet and now wants to play the role of being a lady with a man who isn't sure. Thats not the case at all, its just that she hurt me with those words especially since losing her job was her own fault. I wasn't sure if she was the one who'd be there thru thick and thin...her love did not seem unconditional. I don't want a long drawn out relationship that doesn't go anywhere either but I also don't want to marry someone that's always gonna want to bail when it gets tough. Whats your take on this?