What should I do, if I am continuously dissatisfied with my graphic and web design work?
This is completely normal. I have ran my own design studio for five years and have been designing for ten years.
What you describe is exactly how I feel about most of my work. I like it as I work on it, but a couple of months after delivering I start getting bored by the designs and spot flaws, etcetera.
This is due to the fact that design is an ongoing process. A design, whether it's a typeface, a website or an identity, is never finished. There is no end to it. Every time you look at something, you spot different aspects of it, and your mind automatically comes up with solutions and improvements.
I believe this is inherent to a creative mind, and thus something you'll have to learn to live with.
As for the portfolio: get over it. Put the projects you are really satisfied with upon delivery in it and accept that everything *could* be improved. Most importantly; when you present your work, don't mention the flaws you see in it. You're the only person aware of them because no one on earth sees your work more than you do. Instead, talk about the process, the choices you made and how you got to where you are. Also mention how your design fills in the wishes the client had and what you were briefed in the first place.
And last but not least: cherish your creative, opinionated and critical mind. It might seem a burden at times, but it really is a blessing.
See Questions On Quora