Relationship problems

I love my husband so much and our relationship is great other than I just have no desire for sex at the moment, it’s not fair on him and he doesn’t feel like I’m interested in him anymore which isn’t the case. I just feel tired a lot looking after our son and I’m also back on the pill which could be causing problems. Please can someone tell me I’m not the only one who feels this way or give me some tips on how to get the spark back.