I feel like a bad mom

Clariza
Hi ladies I'm a first time mom; my LO is 6months old; and sometimes she goes into these fits were she cries for an hour and fights her sleeps. I thought it was gas so I give her gas drops, thought it was maybe her teeth so I give her a lil oral gel. I think maybe she is over tired; but I make sure she takes all her naps when she gives me those cues, I guess sometimes she just needs to fuss or is just tired. She will cry for 20min- 45min and sometimes sleep for 30min- 2hrs. The reason I feel like a bad mom is that even though I know she doesn't know I get frustrated; I feel bad because I know she doesn't mean anything she a baby how can I be frustrated. I'm the only one that puts her to bed because my BF works a lot and I'm lucky to be able to stay home because he works hard. So by the time he gets home she in bed, and at night I'm the one who gets up with her. So I dot. Really get a break because she preferred me and I don't like to leave her because I feel guilty. Anyway I just need some encouraging words, because I feel like a bad mom for being frustrated.