Will breast implants make me look top heavy?

Thank you for the question.   You will find that online consultants will not be able to provide you with specific advice in regards to proceeding with breast surgery or not or the selection of specific breast implant size/profile. Ultimately, careful communication of your goals (in my practice I prefer the use of goal pictures, computer imaging and direct examination/communication in front of a full-length mirror) will be critical.
Generally speaking, the best online advice I can give to ladies who are considering breast augmentation surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "C or D cup” or "top heavy" etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate.  Again, the use of computer imaging, may be very helpful during the communication process.
3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery ( after the use of temporary intraoperative sizers).  Viewing the patient's chest wall in the upright and supine positions, with temporary sizes in place, help select  the best breast implant size/profile for the specific patient.
I hope this, and the attached link (dedicated to breast augmentation surgery concerns), helps. Best wishes.

Thank you for your question.
Pictures would be helpful.

Without picture and more information, the answers that you are going
to get will be speculative in nature.

To be sure, see two or more experienced,
board-certified Plastic Surgeons for a complete evaluation to make sure you are
a good candidate and that it is safe for you to have surgery.

I hope this helps.

I do not really know how to comment without seeing photos or examining you in person. In general implants do not cause people to look top heavy.