Hi Natasha25 and welcome.
UC is a disease that is characterised by flares, what you are experiencing now, and periods of remission. The drug you have been prescribed may work very well for you and indeed put you into remission, sending you loads of luck that it does!
The main thing to remember is that remission is just that so there is a chance that it will come back. I am a little wary of the doc that says you have UC, here is this med take it and all will be well as I think it has the potential to lull you into a false sense of security. I hope that doesn’t sound alarmist as I don’t intend it that way, all I am suggesting is for you to remain vigilant regardless of how you are feeling. Even when in remission have your bloods and faecal protection done at least annually and scopes no longer than every 3 years.