Tooth Decay from the Inside Out.

My front teeth were oddly shaped and this caused them to have spaces between them. My dentist that I trusted and went to for years does do porcelain veneers. I talked to him on a couple of occasions and wanted to do them. I never smile much because of my teeth. He said, I was a good canidate because of my good oral hygene. I never had problems with my top front teeth with decay and I'm 41 years old. I had them done 2 years ago. I smile even less now, I have 2 dark spots that can be seen at the gum line through the porcelain veneers. My gums were bleeding on the teeth only with the veneers. I had the top 5 teeth done. He gave me a mouth wash for the bleeding, that did help. I brush my teeth twice a day floss twice a day and use mouth wash. He told me the dark spots was where the gums had bleed and blood got down between the tooth and veneers and that he could clean it out but 1st he had to stop the bleeding. Well, it wasn't blood I go twice a year for cleanings and at my last one he did xrays and said, that I had a cavity that was starting and that he could get to it even though it was on my teeth with the veneers. I had two of the filled and while he was drilling he said to me oh your porcelain the dark spot that I was seeing is because the tooth had decayed from the inside out, but once he got all the decay and filled it, the veneer wouldn't be dark. He said, it's lighting up already. At my next cleaning I was concern because right after the filling like within 2 days my gums became red and swelled and yellow sticky, stinky puss like stuff was coming from the other two teeth he didn't fill. He said, not to worry it was plaque build up to be sure and brush and floss. What? I was concerned about redness and swelling of my gums at the top front teeth only. He couldn't see what I was talking about my gums all looked the same to him. What? I asked him about the dark spot still on the tooth he filled at the gum line I voiced my concern that I was afraid that he my not have gotten all the decay because the veneer when I smile is still dark. No, it takes the gum 6months to recover he told me to give it 6months to heal and the dark spot will go away. What? does the gum have to do with the dark spot? This makes no sense to me. I voiced my concern of my other top tooth that is starting to look dark just like the first one. I asked if it was decaying also. He couldn't see what I was talking about on it either, he did another xray and said, it was fine. I was sent home with an appointment in six months for another cleaning. I'm just really upset because I've spent all this money on my teeth and now my teeth are worse off than what I started with. My gums where the veneers are hurt when I floss. I have a dark spot on the top rt front tooth and a dark spot on the top lt front tooth. The other veneers seem to be fine. Can my teeth be saved? Should I seek a second opion? About the yellow puss like stuff with the redness and swelling. Has he put my veeners on wrong is this why the decay was from the inside out? Help my I don't know which way to go with this.