Frantic evening feeding?

My LO is a month old and often has these frantic evening feedings when she latches on aggressively (like she's starving), begins sucking, then cries out as if she's in pain (sometimes accompanied by kicking), lets go, then latches on again and we repeat the whole thing over and over. Her latch is strong so I know that's not the problem... and I don't think the volume of the letdown is the issue either. Gassiness has been a problem but that is regardless of the time of day, and I don't think it's reflux because she rarely spits up. What do you ladies think? Is she overtired? Just gassy? Combination of both? Or something I haven't considered?