SUDDENLY Server DNS cannot be found

Hi, I hugely desperate. My site was working perfectly and suddenly the page shows server dns cant be found on both wordpress editor and site on every browser. I had added www. to my url in wordpress but i dont think that caused any problem. I also checked the nameservers on my freenom(where i have my domain)and re wrote them with the ones that shows now on my host
what happened to my site??? how do i fix it? i am 4 hours now trying to search what to do but still no success. im desperate. Thanks for your help

Btw, i also want to point that I changed by mistake my url and wordpress url in the wp editor and fixed it with a tutorial going to my databases. Again, suddenly now ine of those data bases has disappeared and cant access to those setting to check if i did something wrong there! this cant be more weird!!

I just checked and it seems to be working fine.