I think the scepticism might also be a defence mechanism and although it could be true that you don't benefit positively while you have this attitude I don't think you can really do anything about it.

For me, I didn't really have this period of sceptical doubt. I have a very good intuition that I trust and on some level I was certain that I'm on the right track, even though this track felt extremely difficult for a long time. The other thing is that some very young part of me had a hunch that it could get something from my T that it had never gotten from anybody and thus stopping going wasn't even an option to me because it would have meant that this young part would have to give up the hope of ever getting "it".

I also agree with the thought that someone else said before that 3 months in psychodynamic therapy is really a very short time and if you generally have a good feeling about the T and you feel that he knows what he's doing then keep going. But if my experience sounds similar to you then better just be prepared that it might be necessary to finally face the depression that you have avoided for long and it definitely isn't pleasant. Make sure you can lean on your therapist during that time!