Breastfeeding is a skill that both you and your baby are learning and for some mothers and babies it is harder than it is for others. Like anything new, it takes time and patience.
Relaxation is important for both you and your baby. If you find you are getting frustrated or angry at yourself while you're trying to breastfeed, stop and try again in a little while.
If your baby is distressed, and if it is possible, ask someone to keep them distracted until you are ready to try again. You could also express for this feed and try feeding from the breast for the next feed.