Had a frozen embryo transfer yesterday. My second one. This morning had some bleeding. Started red and is now brownish. My dr said not to worry. Uterine lining was thick and good yesterday. Thoughts?

Doctor is right. This happens a lot - that's why your doctor is right telling you not to worry. If he/she believed there was cause efor worry and something to do about it, you can be guaranteed he/she would help you. I know it's normal to worry, but it doesn't do any good. Follow instructions, and good luck.
Anxiety help. You seem very on top of all if your clinical findings, sometimes you just have to wait. If your doctor told you not to worry then it's best to find ways to alleviate your anxiety. Look for ways to support yourself and if you have a partner support each other emotionally by talking and doing relaxing things together. Therapy and/or meditation can help. Best wishes an good luck!