48 hrs since my 325cc under the muscle and I look small. Will it get bigger once it drops?

Dear nathyribeiro2,dropping of implants is part of the healing process and this occurs after the tissues surrounding the implants slowly relax, allowing the implants to settle into their final position. It can take about four to six months for the implant to drop down to their final position.I understand that you are worried about size of your breasts. However, you are still in the early phase of the recovery period. Please do allow some time for the healing process to occur. If after six months, you are not satisfied with the appearance of your breast, you can visit your plastic surgeon and discuss your concerns.Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery

I am sorry to hear about your concerns after breast augmentation/lifting surgery. Your plastic surgeon will always be your best resource when it comes to accurate assessment and/or advice. 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. It is very common for one side to settle faster than the other.
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. 
In other words, it is much too early to evaluate the outcome of the procedure performed; your breasts will undoubtedly change over the course of the next several weeks/months.   The vast majority of patients with your concerns at your stage in the recovery process, turn out to be much happier two to three months after the procedure was performed.  Understandably, patients often experience significant emotional "ups and downs" around the time of surgery.
For example, 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. 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. My best advice: rest,  recover, and exercise patience.  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.

Congratulations on your breast augmentation.  It will take up to 3 months for your breast implants to drop into position.  As the implant drops under the nipple areola you will have more fullness in the lower pole of the breast most likely will look further in larger.