I was a Chemistry major at OSU. I know what you're going through right now, it's rough. I took Calc-based Physics + lab, Advanced Inorganic Chemistry + Lab, Calc, and some filler courses all during the same year. Balancing the classes, the recitations, the labs, the elective courses was a pain in the ass. Someone mentioned solutions. Get them. I discovered them during my 3rd quarter of Physics and was able to teach myself. Use them as a guide to teach yourself, not to memorize problems. UNDERSTAND what you are doing and make sense of everything. The biggest mistake you can make while studying is to assume something will not be on an exam or that a certain difficult concept/type of problem will not be heavily weighted. It's easy to skim over one thing and then that one thing ends up being 15-25% of the exam, and you end up with a C, when you knew 98% of the material. Always always always know 100% going into an exam. UNDERSTAND 100% of the material.
Don't go to office hours until you have studied all of the material and understand everything you can, that way you can utilize your time appropriately and ask the questions that you need to ask. Find a nice Physics / Calculus chat/message board. I used irc.efnet.org #physics and #math chat rooms. I don't know if they are still around, but it's worth a look. There were plenty of people there who enjoyed helping.
I know how difficult it is to balance everything, it seems like you never have enough time to study/do assignments. Do everything right away. The day it's assigned, do it. Do not slack, especially at OSU (it's more difficult there than other state schools--they require a lot more of your time and effort to complete the same course than, say, Kent or YSU). Again, know everything! Learn how to study! Learn what works for you. I was an above average student my first few years of college, ~3.2 GPA. One semester, everything clicked. I realized what mistakes I was making when I approached studying. I tried to memorize my way to an A. Memorization is for the birds. You spend way less time understanding concepts than you do memorizing a long list of crap and getting frustrated when you can't apply that shit you spent so much time memorizing to complete a difficult problem (I bet this sounds familiar?). Sometimes, memorization is necessary, but concepts should always be understood. Once I started understanding concepts and studying efficiently, I always got A's. I got a 3.9 in grad school and a 3.9 in pharmacy school.
Take Summer classes. Do it at a local school, preferably one with cheap tuition. Kent State has many regional campuses and tuition is dirt cheap... and classes are much easier, and they offer a lot of online courses. Just get transfer approval (IN WRITING) before you take anything elsewhere. Utilize ratemyprofessor.com . Do not take classes with shitty professors. I highly recommend Chemical Engineering. You will bank with a Bachelors degree. I have a Masters in Organic Chemistry and taught the recitations during grad school. If you go the ChemE route, feel free to ask me for help with O. Chem. Also, with ChemE, if you decide to further your education, you have just about all of the prereqs out of the way for Pharmacy/Medical School.