As long as you maintain the required satisfactory progress requirements (see you school requirements)- usually a 2.0 and completion of 67% of classes attempted.... and you are still at least half time (usually 6 hrs for undergrad), your financial aid will not be affected. If you had a scholarship for the program you dropped, you will probably loose that. Otherwise, next term, register for full time and your aid should be the same.
I was a Director of Fin. Aid for over 20 yrs and have extensive experience in this. If you want confirmation, call and make an appointment with a financial aid counselor. However, unless you have specific program related assistance, they could care less what your major is or if you have a dual major. Also refer to your school catalog in the fin aid section for "Satisfactory Academic Progress" requirements.