losing weight and hair

My cat is 9 years old.  Always been a healthy cat.  Recently, He has been losing weight this past 2 weeks.  I saw him vomit couple times after eating.  I noticed in the vomit their was hairball.  His appetite and drinking water is the same...normal.  I am very worried.  His attitude and appearence is not the same cat 2 weeks ago.  Something is wrong but what could it be?  I have noticed He has a bump on his back.  I took a look at it and looked like a pink bump.  He would try to bite me everytime I touched it.  He is an indoor and outdoor cat.  Mostly indoor.  His tail looks normal. He is losing a lot of hair more than usual.

You should take your kitty to the vet. I have a thread in this forum titled Toby vomiting and losing weight. It took me five visits to the vet before they found that he did have a mass. I don't know if your kitty has anything serious, but it is worth a checkup. For my boy, it was the vomiting after eating that I noticed, and also his fur looked bad, rumpled and not nice and sleek as usual. My vet gave him a shot of convenia which didn't treat anything. It wasn't until I brought him back 3 more times, she finally did an xray. He was still eating and everything but his fur looked bad and he kept vomiting his food, not every time, but enough to make me worried, and especially in the morning. 

If you take him and your vet does bloodwork and everything shows up fine, but he is still not right, take him back and get an xray and continue to post on this site. That is what I did. Your boy could also have inflammatory bowel disease. Or it could be something a lot less serious. No matter what, take him to the vet. Good luck, fingers and paws crossed for you! :-).

I agree with Barb - a vet check is definitely in order. AND please do keep posting. It will help so much to have the support from this forum of wonderful members!!! let's just hope that it is nothing that can't be easily treated :cross:

The bump could be an abcess, but he also could be getting an overactive thyroid - that leads to weight lose and some cats vomit with it.  It also leads to a poor coat.

Definitely take him to the vet.  Hope all goes well.