The words "loneliness" and "worthlessness" are pretty much always emotions or mental states, so they are appropriate objects for "feelings of". The word "solitude" on the othe hand, most often means the actual fact of being alone. However it can also be used to describe the metal state resulting from being alone, and in that sense could be used with "feelings of".
"feelings of solitude" seems a bit odd, i think because of the primary meaning of "solitude" not being a feelign or mental state. But I don't see anything actually wrong with it.