Unappreciated at Work

I am influencing positive change and growth around me at work, or among the people I meet and know, however I am feel like I am not being given credit for what I initiate. This has gradually intensified in the last year. Most of the times people just take my ideas and make them look like they are their own. This situation makes me very sad and I would like to get over that sadness. Should I stop giving ideas or suggestions to people? I think I am volunteering my help too much, but I don’t know how to stop. I have people at work that act like they hate me every time I say or do something. I was very successful and good at my job, but I and lowering my performance by the day and I am losing my passion for this. How do I break this pattern?

I recently took a 6 weeks stress leave, I quit smoking 3 weeks ago, but after a week back at work I feel the same way again and my energy level is lower than ever. I have never been in this situation before, and I would like to perhaps change it for the better. I would like to start my own business, but I am so exhausted that I lack in creativity and fear takes over.