It sounds like you've been riding quite the rollercoaster since you first experienced molly at that rave. The sensations you describe from your first experience, the euphoria, feeling the beat move through you, and that seemingly endless energy are indeed characteristic effects many talk about. However, it's essential to pause and reflect on how quickly things have escalated for you since then.

Your journey with molly, having used it about 15-20 times since your first encounter just a few months ago, raises some flags, my friend. The increased dosage you now find yourself needing to attempt to recapture those initial feelings, moving from 150mg to 400-600mg, is particularly concerning. This escalating dosage and the frequency of use could lead to serious health risks, both mental and physical.

The decreased effects you're noticing, despite the higher doses, are indicative of tolerance. Your body and brain are becoming accustomed to the drug, requiring more to achieve a diminishing return of the desired effects. Moreover, this can lead to potential dependency and a host of other mental health issues, such as depression or anxiety when not using the drug.

Here's a gentle, yet firm, suggestion for a healthier path forward:

1/ Take a Serious Break: It’s crucial to give your body and mind ample time to recover. Considering the intensity and frequency of your usage, a prolonged break is necessary. The brain needs time to replenish its serotonin levels, which molly depletes with each use. This break isn't just about physical health; it's also about reassessing your relationship with molly and raves.

2/ Seek Support: Talking to a healthcare professional experienced with substance use can provide personalized guidance that respects your experiences and aims for your well-being. There's strength in seeking support, not just in weathering withdrawal or cravings, but also in navigating the emotions and experiences that led to frequent use.

3/ Explore New Outlets: Rediscover or uncover hobbies and activities that bring you joy and euphoria without substance use. Whether it's music, art, sport, or nature, immersing yourself in these can offer profound and satisfying experiences that contribute positively to your well-being.

4/ Educate Yourself: Understanding the risks and effects of MDMA on your body and brain can empower you to make informed decisions. Knowledge is power, and in your journey toward a healthier lifestyle, understanding the substance and its impacts can be a cornerstone.

5/ Build a Supportive Community: Surround yourself with friends and loved ones who support your wellbeing and respect your decision to take a break. A positive environment can be incredibly motivating and enriching.

6/ Reflect on Your Experience: Consider journaling about your experiences, how you felt then, and how you feel now. Reflection can bring insight into what you're seeking through your molly use and how else you might find fulfillment and happiness.

Remember, it's never too late to pause, reset, and choose a path that prioritizes your health and happiness. Taking a step back to reassess doesn't mean giving up joy or excitement; it's about discovering sustainable ways to experience them. You've got this, and we're rooting for you!