I had tonsilits a few weeks ago and now i cant hit a note when i try to sing what should i do and will it come back?

Be patient with your voice. It can take some time to recover from diseases that affect your throat, and straining it won't help anything. Start with gentle exercises that are lower in your register until you feel comfortable. Then move towards arpeggiOS that start low and move higher through your vocal range. The key is not to get wrapped up in what notes you can sing, but instead focus on making sure that the sound and feeling are right again.