Hi, stammering isnt oy a speech disturbance but it has to do more with the psychological part! It has a lot to do with the person's self esteem and condfidence. It generally includes a lot of self doubting and experiences of shame.
There are no medication for stammering! However, it can be controlled and dealt with. It does not require a speech therapist, with counseling it will reduce and help you take charge of the situations you face!
Next Steps
One technique that i can suggest is use substitute of words that you think you ll stammer on! it works!
for e.g. if you think you ll stammer on word like 'neccesary' you can use a substitute of it i.e. 'important' , 'essential'