Warm greetings, Melanie! 
Francisco has shared some wonderful resources to draw in happiness- and I agree that the best place to get started is with a shower or bath to wash away bad energies! 
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You can make a special ritual bath/shower by surrounding your tub or shower with things of significance to you- crystals, herbs or plants, figures of animals you connect with, candles, your favorite jewelry, etc. For a structured ritual bath, you may want to look at Taylluna’s Full Moon Bath Ritual . We have a Full Buck/Thunder Moon
approaching this weekend!
If you are having a hard time gathering happiness within you, you can try an alternate approach: banishing negativity 
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The Green Witch on YouTube has some beautiful videos on YouTube that are very peaceful and relaxing to watch- you may want to make yourself a cup of hot tea, wrap up in a fuzzy blanket and watch her video How to Clear Negativity From Your Home. She has a lot of advice for cleansing, purification, and the removal of negativity!
I wish you all the best of luck- feel free to reach out here in the forums anytime! 
Blessed Be!