Thoughts are like the waves of an ocean. They are countless.
Some thoughts will subside while some other thoughts will gush like a stream.
The same old thoughts that were once suppressed may again show their faces after some time. Never become despondent at any stage of your practice. You will surely get inner spiritual strength. You are bound to succeed.
Keep in mind, all the Yogis of yore had to encounter the same difficulties that you experience today.
The process of destruction of mental modifications is difficult and long. All thoughts cannot be destroyed in a day or two. Do not give up the practice of destroying the negative thoughts in the middle of your path, when you come across some difficulties or stumbling blocks.
Your first attempt should be to reduce your wants and desires. Reduce your wants and desires, then the obsessive thoughts will decrease by themselves. Gradually all thoughts will diminish to zero during meditation.