Hello guys!

I just returned from a trip with long and mainly highway miles. At the end of the trip the low-oil indicator light would come on randomly then disappear again. I checked the oil level and it seems like there is definitely not enough oil in there as the dipstick shows oil at MIN level!
I got an oil change in February of this year and have since put 3,000 miles on it. Should I go for an oil change again or can I just top off with 0w-40?
If so how much and where do I fill it?
I'm going down again right now and trying to get an electronic reading to see how many quarts are really missing!

Thanks for your help.
Nick