<human>: I've been dating my girlfriend for a couple years and we've always had a good sex life and are very attracted to each other.  Lately I have no interest in having sex.  I can't think about it. It feels like imagining having sex with a platonic friend.

I'm in a high stress career and have had several projects going on over the last few months.  My depression and anxiety have also been really bad.  This definitely affects my sex drive, but I still have the (lessened) desire to masturbate.  I'm not tempted other people, but I'm worried I lost that physical spark for my gf.  This is my longest relationship and she is my best friend.  I don't want to break up.  Is this normal?  Do people lose the spark and get it back?  Could it just be my poor mental health?

Can you summarize the given text in a few sentences?
<bot>: I'm worried I'm no longer physically attracted to my girlfriend, but it could be my poor mental state.  How can I know for sure?