I am 26, I have very irregular periods, what can I do or take to regulate it?

Irregular menses. You need to be evaluated by your gyn and if everything is normal he/she may recommend bcp.
Natural Therapy. This often indicates elevated estrogen levels. Mostly coming from xeno-estrogens (contaminants in food and water-pesticides, herbicides and petroleum contaminants as in the plastic from water bottles. Try to eliminate as much of this exposure as you can. Consider bioidentical Progesterone cream in cyclical fashion to counterbalance the estrogen; worked very well in my daughters.