Can't cope with my 5 month old

Please no bashing I'm looking for advice. I've always been fine I've done everything for him and he's so used to being picked up and having attention I feel like I can't cope anymore. I get no time to myself and I feel like I'm going ill over it. I hate being alone looking after him I feel like he hates me. My partner works all day so I hardly get help. I'm young and always wanted my own family. I'm just finding it really hard right now I'm really struggling. Is there anything that can help? I don't want to leave him cry because I feel awful and that would make me feel like I'm failing and letting myself go. What can happen if I'm so worn out my health isnt the best and I'm worried something bad could happen.