Should I have went with a bigger breast implant? I got 325cc mp+ Mentor implants three days ago. (Photos)

I am sorry to hear about your concerns after breast augmentation surgery. Your plastic surgeon will always be your best resource when it comes to accurate assessment, advice, and/or meaningful reassurance. 
It may help you to know that a significant percentage of patients at your early stage of recovery will feel that they are too big or (more commonly) too small.
Generally speaking, breast implants will "drop" into the pocket that was created during surgery. The rate of breast implant "settling" may depend on factors such as size of breast implant pocket dissected, tightness of the overlying skin/muscle layers, and size of breast implant utilized. Normally, it takes about 3-6 months (for some patients longer) to see the final result.  Therefore, I routinely ask my patients to wait at least 3-6 months before evaluating the end results of the breast augmentation surgery. This waiting time allows patients to (usually) physically and psychologically adapt to the new body image. 
Many of my patients report that as the swelling around the breast implants (for example, in the sternal area) decreases, they feel that their breasts appear more projecting (and that they have better "cleavage"). Also, in my opinion, the "drop and fluff” phenomenon does hold some validity; as breast implants “settle”, many patients feel that their breasts actually look larger. Similarly, it takes a few months for the breasts to "soften" in most cases.  Most of my patients tell me that their breast implants feel "part of them" somewhere between 3 to 6 months after surgery was performed.  
My best advice: rest,  recover, and exercise patience.  Again, keep in mind, that a significant percentage of patients at your stage in the recovery process feel that they are "too big" or "too small".  In the long run, once patients have adjusted physically and psychologically to their new body image, the vast majority of patients are very pleased.
 
 Best wishes for an outcome that you will be very pleased with.

25ccs is less than 2 tablespoons, or equal to one notch on your bra strap- not much of a difference. Cleavage can't be built. The good news is you have more volume, a fact which will make it easier to create cleavage with clothes. At 3 days post op you are about 1 percent settled, shaped, softened, dropped and fluffed. "Drop and fluff" refers to the fact that as the skin stretches and the muscles relax, the implants move down and out slowly – about 1 percent a day. It’ll be about six weeks before they even begin to settle down, but they’ll be close to 80 percent settled and softened at three months. Watching their progress is like watching your hair grow. You don’t see a difference in your hair growth daily, but all of a sudden you need a haircut. 
Be patient after surgery. Give yourself a few months before making a judgment about your surgical results. You won't know the outcome until then. 
Dr. Ted Eisenberg, Board Certified Plastic Surgeon and Author

Congratulations on your breast augmentation. You have a beautiful symmetrical result in should be very happy with it. Your implants will drop into position over the next 3 months and will look fuller and less widely spread. The distance between the breast as determined by the width of your chest bone and the insertion of your muscles and it is unlikely that an additional 25 cc would make much of a difference. Ask your surgeon if you may do breast implant displacement exercises pushing the implants together towards the midline.