Help!!!

I just returned to work this week at 10 weeks pp and my son has been receiving my pumped milk trough a bottle while I'm gone. I try to put him on my breast as soon as I get home but the last few days he just screams every time I offer it, last night was the worst and after 4 hours of going back and forth my only option was to bottle feed so he would finally sleep with a full tummy. I'm not ready to exclusively pump and be done breastfeeding...how can I save my breastfeeding and ease this transition? We had previously given him bottles on occasion and he never had a problem going back and forth before so what's happening now? I feel so helpless and sad about this...