First off, don't compare your happiness and gold to that of the AI players. One of the running jokes in this forum is the infinite happiness the computer players get.
As for happiness, we might need more info to help you. But here are some tips:
- Lots of city means lots of unhappiness. First tip then: settle less cities.
- Don't settle new cities just to grab land, settle to get new luxury items. On a huge map that's tough because you will probably get a lot of one kind - so make friends with the AI players and trade lux for lux.
- Settling nearing horses, elephants, and stone allow you to build Circus/Stone Works in those cities, which is a nice way to scoop some cheap happiness.
- Just because you pick happiness religion components doesn't mean you are exploiting them. Make sure you meet the condition of the religion option (e.g. settle on rivers, or have a population of at least 3, or whatever).
- Are you conquering a lot of cities? Raze them and re-settle to avoid costly unhappiness issues.
- Are you exploring the map early on? On a huge map you should be able to pick up +10 happiness just from finding all the Wonders on the map.
- Build stadiums.
- Choose the happiness policies in the policy screen - especially the one under Honour for defensive structures or the ones in the Piety tree.
- Make friends with Mercantile city states or any city state with a lux you don't have.