It is difficult to understand how severe a problem this is without seeing your mouth and tongue . I can offer a couple of possible solutions but in the end you will need to seek a clinical evaluation.
Tongue thrusting can be habitual or the result of an underdeveloped (small ) maxillary arch and a larger than normal (caused by medical issues/meds)tongue that just tries to 'fit' .
It can also be a side effect of habitual mouth breathing ,allergies that cause open mouth breathing habits or primary /secondary speech problems.
The usual therapy for tongue thrusting is some variety of appliance that fits on the teeth (similar to a night guard) and has prongs that interfere with the tongue as it thrusts forward, causing the habit to subside.
Some doctors treat with tongue and mouth exercises to train the muscle to work more efficiently.
Others refer to speech pathologists who are trained to help you with tongue excercises and articulation that is sometimes hampered with this malady.
Removing part of the tongue is the last thing anyone would consider. If the tongue is enlarged due to a malformation or medical issue or medications, it is a possible that this may be considered.
In the meantime, from your description, I can understand that this is a formidable problem. Before any bridgework is compromised (expensive) I would advise consulting your general dentist and if he/she is not versed in a cure then get a referral .
Please ask me more if I can help further.