Sleeping at night

Anyone's little ones still not sleeping through the night? I am at my wit's end and it's effecting my mood negatively and I have no idea what to do. My first was not this bad. But this little guy is waking up ever 3 hours still and I don't know how much longer I can keep this up. I will say he was sleeping through the night for a little bit then it all changed around 11 months.