un provoked cat aggression

Hi, I have a siemese cat rescue, about a year old. He is not fixed and I feel that may be the problem, however I have never had a cat attack so much, unprovoked.

After a recent emergency surgery, I return home, knowing the little guy is anxious, I feed him, he lays with me I yet I sense that he is anxious. A couple hours pass and I walk to the bathroom. He was standing on all fours, in the corner, next thing I know he jumps to my pelvic area and gets me good. Mind you this is very close to whet I have had my incision, less than a week prior. If he was a few inches to the left I would be in the hospital.

He has been aggressive at times, recently attacked my brother and girlfriend.

I love the little guy, but with my recent health problems I am really considering a shelter. Please help.

Please consider neutering him.  His hormones are coursing through his body causing him to act out.  He is unable to control the hormones.  If you do not neuter him soon, the behavior will become a part of him and it will be harder to undo.  Once neutered the hormones are rid of his body ( this takes about 3 weeks after neuter), he should calm down.  You can find low cost spay/neuter clinics that will neuter him for about $50.  Please consider getting him neutered ASAP.

Also do you ever play with him?  Play therapy is essential for cats.  Try a da bird wand toy or other wand toy or even a laser pointer.  He is still young and he needs to work out his energy and aggression.  Follow the theory of hunt, catch, kill, eat, groom sleep.  You play with the cat with a wand toy to foster the hunt, catch, kill,  Then you offer a special treat or small meal for the "eat".  Next the cat will groom and take a nap.  He really needs to get some energy out.

Since he is not neutered please please do not allow him time outside.  He will wander far and wide in search of a mate, getting into fights along the way.  Also not to mention, impregnating female cats.  Neutering is the best option.

Thank you for the reply! I will get this done, asap. I do play with him quite a bit, but I was gone a few days, post op. I have toys etc, and I never let him outside.