How to get out of this mess?

Please dont judge i know it was stupid but my kids father is demanding to take my kids away and not pay child support or get 50/50 when he doesnt have a job and gets high all the time. Iv been dealing with so much emotional abuse the past 4 years and im exhausted. Iwant to keep. This out of court but he is making it hard to co parent and really just wants to take the kids as long as he wants whenevr he wants. The part where i strongly fucked up is when me and my bestfriend found his new number on snapchat. He changed his number 3 weeks after we split and i couldnt BELIEVE he was trying to disappear. He also told me he was moving out (never did) so i thought he was trying to dodge child support. He didnt ask the kids for the whole month and i kept trying to look for him. When he changed his number we found it & i was going to use it in case i needed that info for child support. I had a WEAK moment and texted him. Of course he replied back asking how i got his number and i lied and said my "Caseworker" gave it to me and theyre able to go to his family and even ask for him if he hides. I KNOW STUPID. This is all in writing and i wish i could of just told him i got it through his snapchat and i didnt realize how bad i look lying just because i didnt want to look stalkerish but still im going to end up looking crazy. He never replied back to me. I asked to make things work in one message saying i didnt want to go through this but then stoped and tried to make it about the kids but we just kept arguing about it. Im scared and worried if this is going to be taken to court. He has alot of bad shit to himself too so i dont know if hes going to look bad trying to bring me down or look crazy. No one has a RO against each other.

Again he smokes/uses drugs

Has no job

Made no effort to see the kids the first month until i mentioned child support.

I have proof of him leaving to go get high all the time.

My son got sick once and he was no where to be found. My dad who lives 45 min came to get me and my son and took us to the e.r and he never showed up then said he thought "i was lying" i have discharge papers.

He did lyft and someone contacted lyft directly and made a complaint that his car smelled like canabis and lyft will not tolerate that and they gave him a warning .

The only really good thing he did was take me to the kids appointments but thats because i MADE him take me and go since he did not work at that was the least he could do.

Is there anything i should watch out for?

I really dont want to go through this

My sons birthday is also next week. I ask if he planned to see him. Told him we will have a small cake and food to celebrate and hes welcome to come. He didnt reply. If he doesnt call or attempt to even try to see him can i also use this?

This is the text i sent.