Help!!

Okay so, this is a weird subject for me but whenever I masturbate (even stimulating my clit) I get to a high point and my legs clamp shut for a minute, but i never cum, afterwards im really exhausted but still feel like I haven't reached an ending point so it just makes me uncomfortable. What should i do, or what would you recommend trying, I'm to young to buy toys so that option is out of the window.