Stressing about breastfeeding

I naturally have a lot of anxiety. It really stinks that you can see what and how much baby is getting. I really don't feel like my daughter nurses correctly. I feel like she's only sucking half of the time that she is actually on my breast. The other half she is just sitting there with it in her mouth. I try playing with her feet and cheeks to wake her but after my let down she just doesn't seem interested in sucking anymore. She has 5-6 wet diapers in  a 24 hour period and poops 5+ times a day but she is still not awake very much at all and that worries me. She will be 3 weeks Friday. Would it be silly to take her to the doctor just to check her weight? I'm seriously contemplating just showing up there and asking them if I can use their scales. She also has a lip tie that worries me. I don't believe she has a tongue tie though because her tongue is always out. My two other children have lip ties as well but no tongue tie. Someone please give me some suggestions to calm myself down about breastfeeding or tell me I'm not crazy for worrying.