TTC story with some questions

Hello! I just wanted to share my story and ask a few questions.

My name is Alea, I'm 26. My husband and i have been TTC for a little over a year now. I was on the pill from ages 14-21 then tried nexplanon after a year and a half of not having a period (because of the implant) i had my period for 5 weeks straight. My dr put me on some estrogen pills to see if that would stop me from bleeding. It didn't. Got the nexplanon taken out. Got back on the pill at 23 until Aug 2018. I got my period pretty regularly the first few months. My cycle days were between 32-35 days. Then in February 2019 i had my period the 8th-11th then all of a sudden my period didn't come back. I had all of my hormone levels tested everything was normal. I had an ultrasound everything was normal. My dr put me on Medroxyprogesterone for 10 days to see if it would "jump start my period" i took the medication for 10 days then 2 days after i stopped taking that medication i got my period. May 31st-June3rd. Then we waited to see if i got pregnant or if it came back regularly. Neither of those things happend. I had another ultrasound a few weeks ago and everything again was normal. Then my dr gave me a referral to see a reproductive endocrinologist. I have that appointment set up for this Tuesday. And this morning i woke up to AF after over 100 days without my period. Which was very random and unexpected. So yeah, thats ny TTC story up until this point. Now for questions.

1. What should i expect from my endocrinologist appointment? What questions should i ask?

2. Does anyone have a similar story and can give me words of encouragement or advice?

Thank you for taking the time to read my story. I hope everyone has a great day ♡