Nortriptyline

Has anyone had success wth this TCA I stated 25 days ago for anxiety, depression and PTSD .i am on 75mgs daily and know I can go up to 150. Only side effect has been higher pulse rate and constpation. I had an ekg and blood test to see if I was in the therapeutic level, I noticed many people take really low doses. Has anyone seen improvement. My psychiatrist said it can take 6 to 8 weeks. Anyone have any luck on this. Zoloft worked for 23 years and pooped out. Prozac didn’t work or Lexapro or Effexsor completely haven’t tried Paxil yet. Please some encouragement.