Let me ask you something, would you rather be going to school for a few extra semesters and end up doing what you love? Or get your degree in something you don't really appreciate and not enjoy your job for the rest of your life? Hopefully you picked the first option.
Being thrown out into the real world is scary, but it is worth it. You get to experience so much more. You also realize what you have been missing out on. With starting off studying something you thought you loved, to then change it in the blink of an eye is quite a challenge.
It is a good challenge though. It challenges you to think more outside the box than you ever thought possible. Why does it do that you might ask? It is because you had to dig deep and let your emotions surface to tell yourself that this isn't what you want to do for the rest of your life. You want something different, something better for you in the long run. You needed to find that courage to tell yourself that it will all be okay and that it will be worth it.
Once you jump into your new world and experience your change for all that is supposed to be, you will immediately feel better. Going to class won't be a burden anymore. It will be something you look forward too.
Experiencing this new change is what will alter your life. If you're too scared for this new change, you need to find strength because if you take that leap into a new world, it will be amazing.
Another thing, don't worry about credits. Yes, they are important and everyone wants to graduate on time, but in all reality, who cares when you graduate. At least if you are studying what you love to then in the future be doing what you love then take your time. If it takes you an extra semester, great. If it takes you three extra semesters, awesome. No matter what the time difference is, go and experience it.
I promise you this, once you change your major, it will be difficult, but you will be so much happier. You will actually look forward to homework, not dread it. You will put all you have into your assignments and not only do the bear minimum what is expected of you. You go above and beyond because finally you know what you want, and you won't let anyone or anything stop you from getting it and achieving your goal.
Jump into that ocean and see what you can find. Experience what the waves bring you, good or bad and just take a ride. Embrace it.