Meadsie I know where you are coming from. I've been there.

My DD had very slow weight gains from the start and in those early weeks sometimes didn't gain much and even had a few losses thrown in there too (we had many BF issues also that lasted til DD was 4mths of age!)... weak suck and poor attachments for weeks and weeks led to low milk supply so my milk had trouble establishing properly in the early weeks and therefore DD had trouble gaining weight. She was also a tired lazy feeder so would fall asleep at the breast, she'd get exhausted easily. It was tough. A big cycle!

Every time DD was due to be weighed (weekly) I would get so nervous and felt like such a bad mum if she hadn't put on much weight even though i was working so hard to get her to gain weight (we even had top up feeds of EBM and formula for weeks at one stage) on top of Breastfeeds. When all the other mum's in my mum's group had their babies weighed and were putting on 300g a week in the early weeks my little girl was maybe only putting on 80g in a week!! Sometimes less.... it got me really down but I just had to take each day at a time and look at the weight gains over the course of a month rather than weekly gains..... that made it easier. Some weeks were good others not so good....

It wasn't until DD was about 6 mths old that I actually started to relax about her weight gains as from about 4-5mths old her weight gains seemed to be really good and my milk supply great etc and everything FINALLY fell into place for us.... that will happen for you too and you won't always be so worried about these weight gains.
And remember too some babies just aren't big gainers of weight, as long as bub is happy, content, responsive and has plenty of wet and dirty nappies then usually all is going well!

You are doing a wonderful job.