Not getting full time hours/getting sent home

Hello! I was hired at a very popular fast food chain to work in kitchen. I was hired as a full time employee and I asked for 35 hours or more a week and they agreed and were happy that I wanted hours. I’ve been there for a month and not once have I gone over 34 hours, I’m actually going down in hours and this week I’m only getting 21 hours. The other major issue is I’m getting sent home an hour early before my shift ends on most nights because labour is too high so I’m losing so many hours between that and my unpaid breaks, so in reality I’m working part time right now. I’m not sure if I should start job hunting again since it isn’t meeting my expectations or if I should say something to my manager?