Bare with me here,

I am 21 years old I have 2 beautiful kids a 3 year old and a 5 month old i am a stay at home mother.. Who dropped out of highschool when i found out i was pregnant at 16, i regret it so much. My husband..works and pays for everything while i get the luxury of staying home with our kids, heres the thing they won't always be here.. They will be in school before i know it and i want more from life.. I want to become ethier a nurse or a ultrasound technician. How do i do this ? I need help i don't have family or anyone to talk to, i need someone to point me in the right direction. I would love to get my diploma but if i can't GED is fine also.. Is there any online free classes i can take to pass the test? How much will schooling cost? I have so many questions to ask.. And no one to turn to and ask. I'm more so worried about how much school will cost..someone please help me! Thank you so much, I get depressed and stressed just thinking about it!