Cats 101

Hi everyone. I have this cat for almost a year now and have started behaving weird. And its weirdness quotient increases day by day. It has never even tried showing symptoms that it is now. Has started biting and also is scratching herself bad. Seems painful and also looks destructive. I really don’t know what to do. A friend has advised to contact cats 101 that tell us everything about our small and pretty feline. Help me out, rather help the poor baby out. Thanks in advance!!