I Have Been Diagnosed With Asthma That I'm Having Difficulty

I have been diagnosed with asthma that I'm having difficulty managing. I have shortness of breath, wheeziness, tight chest and limited ability to do any physical exercise. It's causing me great distress and at night I have trouble breathing while lying down. I have been provided with several drugs/inhalants that don't seem to be alleviating many of the causes of the distress. I'm taking Singulair (PM), Serevent (2 puffs daily) albuterol (every 4 hours as needed and Nasonex (2 sprays daily). All of this medication has only helped in very insignificant ways and for very short periods of time. Would you recommend taking a long-term asthma control corticosteroid inhaler in addition or instead of the above? I've done my research on WebMD. I am also taking meds for high BP, high cholesterol, a blood thinner for a stent
inserted this last summer and common supplements. What might you suggest?