Help?!

Ok here's my story . I need opinions please . I have a 3 week old baby and I breastfeed her. She spits up quite a bit not every feed though . She has been so fussy lately after every feed mostly at night . I change her diaper, burp her (sometimes it's hard for me to burp her) I rock her to sleep and once I put her down to sleep she goes to fussing. Idk what it is. I try everything gas drops and gripe water but she still is fussy. Idk what's going on!!? Help please?!