Worried about my cat. Brown tint on her fur.

Hello everyone, this is my first time on this site and I have no idea what i'm doing so lets just get on with this..

I have a One Year old domestic short white hair. Today, I went into the kitchen and my cat had a light redish brown tint on her fur, I looked around my house to see where she could of gotten the colour from and I couldn't find anything, I tried to wipe it off and some of it came off, I would like to know if that's normal?

I also have recently been worried about my cat, she doesn't seem like her self , lately she has gotten really clingy and won't leave me alone, she's following me everywhere, when she is not following me she's sleeping alot more than normal. In the past two weeks she has put on a tiny bit of weight, and alot in the head, she use to be a really skinny cat now she's just a little bit chubby. She looks really tired and just doesn't look like her self. She's licking her self like every 20 minuets which she normally does not do. 

I would really like to know if that's normal?

Quick question - is your cat spayed?

Yes.

Is she frontline protected? Sometimes flea dirt can appear reddish brown especially when wet and if she's cleaning herself as most cats do it could show more with a white cat.

I think you should bring her to a vet.  Noticing small changes is important, and a vet can help you to make sure that all is well.

By weight, "in the head", do you mean facial swelling?  If so, please don't wait, get her seen immediately.  Any time you notice unusual behavior, patterns, and knowing kitty isn't feeling well, warrants a vet visit right away.

No something is on her fur, dust dirt possibly from a vent, something has blown onto her

or she rolled onto something, indoor only kitty?  Any pictures to share?

*Everything is more noticeable on white kitties.