Mazda 3 oil change leading to problems...

So I have an 09 mazda 3 did my first oil change today.

Took off that plastic underchasis, located oil pan and oil filter... Took off oil pan bolt and drained system till it was just dripping, took off oil filter and replaced. Filled with about 4.25 quarts of 5w30 oil...

Closed it up ran it for a bit and problems started...

Put it in reverse to back out of area I was working and it was Very rough... but idling was fine... putting it in drive was somewhat better than reverse. Was able to drive though within the parking lot I didn't dare take it further...

I let it get to operating temp, let it cool down a bit and checked oil level... which showed it to be much above high.... So I double checked it a few times, then ultimately reopened the nut on the oil pan and tried to drain some... what came out was dark fluid similar to the old oil that was coming out, maybe a half quart came out then stopped... no new oil no more old oil came out... But the oil level still showed it was very high.

I thought maybe I overtightened my oil filter, loosened that up and ultimately took it off and some more old oil looking fluid came out then stopped...

Still the car idles fine...

Triple checked EVERYTHING, and I did it normally... didn't rough handle anything didn't loosen anything I shouldn't have... I decided to try to drive the car again... this time Drive/Reverse makes it go no where, almost like the tranny's shot. (which it wasn't before)

I check transmission fluid while the engine is at operating temp and the meter is completely dry...

This was my first oil change in Mazda3, but I KNOW what I took out was not transmission fluid... It was dark, and oily... and felt like oil... Tranny never gave me a problem in the past, the fluid that came out was in no way red/pink and did not smell like transmission fluid... just felt like oil.

I am at a complete loss... I have No more ideas, talked to my brother who also knows about cars and he has no ideas.

Maybe you guys can help?

Thanks in advance.

-Dan

"I check transmission fluid while the engine is at operating temp and the meter is completely dry..."

Auto transmission? I assume by meter you mean the transmission dip-stick? Exactly
where was the drain plug you removed? Photo?

Over full engine oil level, empty transmission indicates you drained the transmission
fluid, not the engine oil. Engine oil drain plug is on the rear side of oil pan toward
firewall. It's left of the center of the car and can be removed without removing the
under engine tray. I'm familiar with a 2008, I don't think a 2009 changed.

Clifton