I'm hoping someone can tell me they've had similar problems! Apologies for the long post!
DS is nearly 4 weeks old and is my first. Birth was fine but he never latched on to the breast and always just fell asleep. To cut a long story short, no one could get him to latch, they were very busy so we ended up going home bottle feeding expressed milk (I didn't get on with cup feeding).
We discovered he was throwing his tongue back and even very experienced people at the breastfeeding clinic couldn't get him to latch with nipple shields. We tried cranial osteopathy then a private lactation consultant diagnosed posterior tongue tie which was snipped at 2 weeks. We started trying to breastfeed and he would latch after this with nipple shields so a few days later (when DH was around) we started to exclusively breastfeed. Some feeds took ages but all went ok for 4 days til I got mastitis, then feeding started taking even longer and was fairly constant. Health Visitor advised on Friday to top up with EBM or formula as thought he was too tired from all the feeding and had not gained as much weight as she would like. We have been doing that for 24h now and I am worried we won't get back to breastfeeding. I also find the nipple shields frustrating as he keeps knocking them off with flailing arms. It feels as though all I have done for 4 weeks is feed or express or think about feeding him. It is reducing me to tears quite frequently!