Im in need of some advise please help.

I have been together with my girlfriend (27F) for more than 4 years and we are waiting for our bto flat in 1.5 years time

Recently she has become easily irritated and extremely argumentative.

For example, she told me something in case I knew about it. Then i replied that I didn’t know about it. She snapped at me, saying she didn’t ask me and she used the words “in case” and I should reply this way.

I’m really clueless what she meant. I said that’s normal the way I replied.

Another example would be she told me that she changed a post over text. So I replied her saying “Ya lor u changed your post”. She got angry at me, saying i should not repeat what she say and I am really weird for replying this way. I’m really clueless what exactly I did wrong.

This has been happening on and off for many weeks, every other week she will be unhappy about a reply or something I said to her. When I asked her whats wrong, are you ok? , she said ” U saying I’m not normal for scolding u?”

On a separate topic, she recently told me that 2 of her family members are on medication for mental health issues. She insists that she is normal and if I should leave her if I don’t think she is normal.

I notice that she is very particular about cleanliness. For example, she will avoid sitting on the mrt because she thinks they are dirty. Sometimes she would still sit on them but only if I want to sit.

Another behaviour i noticed was that she can choose to bathe without soap for many days claiming that using soap is risky because she may not be able to wash them off and make her skin itch.

I am really clueless as what i should do and we are at the stage that I should be proposing soon and I need advice as to why is she behaving this way.