A tongue can actually swell for a variety or reasons, and this condition would be called "macroglossia." Has your tongue always felt this way, or was it aquired over time? There are several conditions and diseases that people are born with that explain an enlarged tongue, but even more causes for acquired enlargement, including:
- Endocrine disorders - such as diabetes, hypothyroidism, cretinism
- Inflammatory or infectious problems - such as an allergic reaction to foods or toothpaste, or a minor throat infection
- Acquired medical problems - neurofibromatosis, uremia, myxedema, and others
- Trauma to the tongue - biting it too hard, hemmorrhages, exposure to radiation
- Abnormal growths - neolasias, cancers, tumors
Also, the pink color you mentioned might be indicating some kind of nutrient deficiency, such as folic acid or iron (anemia), and might also lead to the enlargement.
It's good that you have an appointment, as further diagnostic testing will be needing to determine the cause and appropriate line of treatment (which will vary according to the nature of the problem). Blood tests are certainly indicated here to rule out nutrient or endocrine problems, and possible infection or inflammatory reaction. In addition to case history, imaging studies are occasionally used as well (CT, MRI). Depending on the cause, medications may need to be used. For example, if the swelling is due to allergies or immune reaction, antihisitimins (such as benadryl) and avoiding the trigger factors would be the key to treatment.
You can view more about the possible causes for macroglossia here: http://www.wrongdiagnosis.com/symptoms/macroglossia/causes.htm
Let me know if you have any further questions, and I hope this helps!