Allergy?

My son is 8 weeks old tomorrow (3 weeks adjusted). We have had some struggles breastfeeding since the beginning, but he’s been able to gain weight well and his latch has improved. For the past couple of weeks, he gets so upset when trying to nurse. He will just cry and cry, especially right after he nurses the first side. I sometimes can’t even get him to take the other side. He has also had an increase in reflux, gas, and spitting up. I know some of that could be related to him crying. My diet hasn’t changed, but I feel like it may be my diet effecting him. Does anyone have experience with something like this? What did you do?