Hello!
You took too much, too closely together.
You've basically pushed your brain a bit off-balance, and it's going to take some time for it to get sorted out again. Think of this as being a bit like a longer-lasting version of being dizzy after spinning in circles; it sucks, but it's not permanent. It's hard to say how long it will take. You might feel right as rain in a week or two, or it may take months. In the meanwhile, take it easy and be kind your brain and body.
The more technical explanation is that MDMA releases a huge flood of the neurotransmitters that your brain uses to regulate itself (particularly your emotional state and perceptions.) In response, your brain tried to tune out that overload of a signal by making itself less sensitive to its own neurotransmitters. So, right now your brain isn't as responsive to the signals that normally keep it running smoothly, control anxiety, etc. Over time this tolerance will go away and your brain will start acting like its old self again.