Ask for some career advice

Hi all,
I've been around in wenxuecity for a while, most people in this career forum is polite and professional (better than those guys in "return to china" forum, i think). I have been in U.S for 7 years. Got my M.S degree in Aerospace Engineering from a non-top school in 2000 (Yeah, i know lots of people don't know what the hell is that). I started working as a software engineer right after graduation, since the job market was still hot by that time. The company is small, a government contractor, after i join that company, it growed from 17 people to over 120 over last 5 years. I would have to say i got valuable experience by working in that company , and i got my green card from that company too. Recently, i switched to another company, still a software engineer. The reason i changed job is that I feel my old company is too boring and going downward as well and the political environment sucks too. So I thought it would be better for me to change to a new environment.
After staying in the new company for a week, i suddenly felt i am kind of lost. What's my career goal? Am i gonna write the code after I am 40, 50? if not, what can I do and what i should do start from now on ? All these issues bumped into my head and make me nervous.
Up to now, i still quite enjoy technical job and still like writing code. My primary skill is in low level development, driver, BSP and embedded system and lots of other stuff. I do have broad range of knowledges and very strong self-learning capability. But I don't have a Ph.D though, didn't finish it.
I believe there should be some one in this forum who experinced the same feeling as me on a certain stage or better, who has passed this stage and set a very clear career goal and have reached it.
Is there anyone who can shed some lights on me?
Thank you for reading my post and have a good weekend.