I bought a Model 3 in August 2018. LR RWD. I DID get the $7500 tax credit that year. However, less than a year later they reduced the price to where I could have bought an AWD for less than my RWD Model 3. But, I did have the enjoyment of owning the car when it was still pretty rare to see a Model 3 on the road. And, I was able to buy EAP which isn't available anymore (until last week and only until the end of September). It is frustrating to see them drop a price a few thousand dollars (especially if it was a day or two after you took delivery) but I would say just enjoy the Tesla and don't look back. Had it been within a week of your picking it up you could have taken the vehicle back.
The funny thing I've learned about Tesla pricing is it isn't always as it appears. I ordered my Model Y in December. Paid $1500 for upgrade wheels (which were listed as 19") and the upgrade wheels in production were actually 20" and cost $2,000. My build reverted to the 20" black wheels and kept the price at $1,500. I also ordered FSD at the time for $7,000. But, my Y was $52,999. So, when it came time to finalize, it was after the $3,000 price reduction, I did pay the new $8,000 for FSD and $2,000 for the wheels. However, my net price was still $500 less overall. So was it really a $3,000 price reduction? Nope. Just smoke and mirrors and not much of a different price actually.
Enjoy the car and don't look back....just know that you are helping the environment and having a LOT of fun driving a fantastic vehicle.