This started happening with my DD1 when she was a similar age. I too was at a loss; all my research suggested it was a 'nursing strike' but these are only supposed to happen in much older babies.
I won't lie, it was really really tough. And the more anxious and tense I got about feeding, the more inhibited my let down was and the more frustrated my daughter got. So it was a vicious circle.
For us, we had lots of issues feeding into making breastfeeding challenging. I had suffered a massive PPH after an EMCS, was highly anaemic, and DD had a severe tongue tie that was only diagnosed and snipped (privately) at 13 weeks. So we had supply issues too, which I tackled with domperidone and a hospital grade pump. I'm only telling you this to give you the complete picture -- hopefully these problems don't apply to you too.
Anyway, the fussing, fretful, unhappy behaviour at the breast did pass. I tried biofeedback methods to help calm me down and encourage a better let down -- maybe google if this appeals. I even tried Bach's Rescue Remedy.
I also tried different feeding positions to help 'trick' DD into latching on and getting on with it, as well as plenty of bathing together and skin to skin. One of the MOST successful things I found was latching her on as soon as she woke from a nap, as she was a bit more fuzzy and amenable, for want of a better phrase I suppose her guard was down. Does your DD have a dummy? It's a controversial thing but if she does, maybe give her that to calm her down while you get your boobs going with a bit of hand expressing first. That way she might get some instant gratification as soon as she comes to the breast.
It got better, but it was a slow process and our stash of EBM was well and truly depleted by the end of it because sometimes only BM in a bottle would do. Persevere if that feels like the right thing to do for you and yours; the good news from my story is that we went on to breastfeed until my DD self-weaned at about 2.5.
Please do PM me if you want to talk about this some more.