Dont know what to do! long!

I know I have ppd. I feel guilty about everything. I feel overwhelmed. I feel like I am drowning. I felt like I was doing ok and was able to function some what normally. This past sunday we got a puppy and it sent me over the edge. I feel like I can't take care of my son and that's all I want to do. I don't have the patience, time or the energy to train this dog. SO has been wanting to get this dog forever. I have a problem saying no to him and now I am in this situation. I had a major meltdown this morning and told him what was going on. He doesn't understand and says I should use my head and figure it out. Everyone I talk to understands and says I am taking on too much too fast. I had a doc app for an iud insertion and told her what was going on. They told me to talk to a counselor and they didn't offer meds because it could make it worse. I don't feel like talking to a stranger but will because I know I need to. I wish he understood. I don't know how to get pass this and I dread being home alone with my son and this puppy. He won't get rid of the dog because we have 1000 invested just from buying him and going to get him. I am sorry if this is long and I am rambling. It feels great to get it out though. Thanks