I feel for you. I was in kollel for about six years and then went to law school, and graduated in 2011. It was extremely difficult for me to enjoy school and study because I felt that what I was learning had no intrinsic purpose. When I expressed these feelings to my Rebbi he laughed and said that providing for one’s family is extremely fulfilling. At the time, I was dissatisfied with the answer and felt misunderstood. However, after actually bringing home some “dough” I see that we was right. Additionally, I have found a job in the legal field that involves people and gives me some satisfaction.
In short, my humble advice to you is:
1) Realize, that your feelings, while coming from a noble place, may be coming from a theoretical perspective considering the prospect of working in the abstract, and may change dramatically
once you enter the practical phase and actually start providing for your mishpocha.
2) In most jobs you are helping others. While it may not be dramatic as saving lives or marriages, in almost any field, you will enter you can be providing services to others in a pleasant, honest and giving manner, (see Rav Dessler Kuntres Habechira), as well be a good colleague to your co-workers, enhancing their lives, and possibly making a Kiddush Hashem to boot.
3) The Chovos Halevavos in Shaar Habbitachon writes that Hashem placed in each person a desire or atttraction to a certain area and a person go with inner voice in choosing a profession, and then have bittachon that ultimately hashem is the one providing.
As far as your other issue – I have found a job in a frum office and I don’t know how I would deal with a non-frum situtaion. Obviously though, having a rav with whom your are in constant contact, especially at the initial stages of your career will go a long way in assuring that you reamin the ben torah you are.
Best wishes for Hatzlocho