According to my boys, basic training wasn't that bad... once it was over
Your parents won't be able to reach you for a while. When you do get to call them it will be for about 5 milliseconds or the time it takes you to give them your address and say "yeah I'm fine but I've gotta go". Whichever is shorter. They spend the first couple of weeks emptying your mind and deleting any thoughts that you are an individual (army of one my ass will cross your mind

). Then they start the team building. By the end of it you'll be a different person but that will pass
It's unbelievably important that your family send you letters. I wrote my boys almost daily. I got almost nothing back. That's just the way it is. You aren't going to journalism school

so they don't give you a lot of time to write. I would even suggest that your dad post your address on the forum but on second thought if you get too much mail you'll stand out and you don't want to stand out. Ever. At least not like that.
Each TI is different (the USAF calls them Training Instructors. I don't know what the Army calls them). My oldest got his letters right away. It was almost a month before my youngest got his letters yet I was getting letters from him wanting to know why I wasn't writing him (talk about a nightmare...) and I was writing furiously every day.
I hope that you are running a lot. And doing a little weight training. It won't be enough but it will be better than no training at all.
Do what they say when they say to do it. They are on the lookout for leadership skills but I don't know what their criteria is.