Weird experience during meditation
It’s called a “kundalini awakening” in yoga, and “tummo” in Tibetan Buddhism. Seek out a qualified teacher who can guide you through this, as it is both a beautiful and a possibly dangerous event. You can get lost in it and suffer various emotional or motivational problems, but properly harnessed it can launch you into major spiritual advancements. The key is to understand what is happening to you and how you work with it. But be careful, as many yoga teachers are ill-prepared to help with something so profound, as ‘modern’ yoga practices are often focused more on external body forms, rather than on energy movements in the subtle energy body.
Congratulations, and good luck.