2003 Saturn L300 6 cyl Automatic 116000 miles

So about 5 or 6 days ago I notice my car making a noise...like a ticking noise or knocking I guess you could say. I went today to get my oil changed and the place refused to change my oil because of the sound. Thats when I realized that I was almost out of oil. Never have done that. Always changed at 3,000. After I added enough oil, the sound is gone and there is no knocking sound at all. But once I got home after traveling 2 hrs to get back home. I noticed an oil leak in front of the engine. I thought I noticed that before but now I am for sure its there. Is this fixable or did I ruin my car?