AMH levels

So back in 2019 ( I was 26 y/o at the time) I had my AMH levels taken at my first fertility clinic, while going under diagnostic testing to find out why we weren’t conceiving.

It was 0.93 

I was told by that RE, that I have a diminished ovarian reserve.

I recently started to see another RE at a different clinic, who also just checked my AMH levels.

It was 3.00

On my saline sonogram he also found that I have a total of 19 follicles 😳 which he anticipated only 5-10 given the prior AMH results.

I am kind of in shock, and very confused by the large increase (not mad at all by it 😉) I am just curious, what could cause this? I was not doing anything special to make it increase! Has anyone else experienced this?