Raising a baby, that too when he/she is helpless and totally dependent on you is stressful as well as rewarding. When you deliver your baby, your body would be ready to nurture your baby. Holding your baby or feeding her/him, if done with right posture after taking proper care of your own health should not lead to depressed mood. It should rather lift you up. There could be other reasons for your depression.
Let's find answer to few questions to begin with.
1. Along with the responsibility of caring for baby, Are you over working by engaging in more than you can manage or underworking by just confining yourself to baby..?? In first case your body as well as mind is getting boggled with too many things to take care of (Here you need to sort out your priorities & engage only in few things which are most important ) and in second case it would seem as if baby is holding you back from engaging productively and expanding your world (Along with the tremendous task of shaping & caring for another life which is your own reflection, find out what all you can engage in without affecting the requirements of baby for while till he/she needs you ).
2. Depression is a state of dip in the mood triggering insecurities & negative thoughts or the negative thoughts & fears leading to a dip in the mood. In either cases we have 2 components namely thoughts and feelings involved. What sort of thoughts are bothering you..?? What are your feeling communicating to you..?? Do you feel over burdened by the responsibility of baby..?? Do you feel you, yourself are missing the care, respect you deserve; in turn leaving you sad & helpless..?? Remember that you are to care for yourself as well as your baby. Only if you feel healthy & happy inside, your baby can be nurtured well. Make your well-being your first priority so that you can give your baby all you have.
3. Your paediatrician will be the best person to comment about the optimal breast feeding interval for your baby. Take her/his suggestion in next visit. Do you get tired or feel any pain when you breast feed..?? In this case do consult a gynaecologist for a professional assistance.
I am sure you would successfully manage your own well-being & also bring up your baby in a loving environment. Take Care.