You are likely connected to a congested free server. Disconnect and reconnect repeatedly until you get a faster one. Alternatively, try connecting to a specific location (e.g., Germany instead of the US).
If you run out of data, you can use a secondary free proxy (like the one built into Opera Browser) for the rest of the month. However, those are generally less secure. vpn zenmate extension for chrome free
If you need to stream Hulu, BBC iPlayer, or Netflix regularly—or if you want to protect your entire device— upgrade to premium . The free version is merely a "trial" with a permanent 2GB leash. You are likely connected to a congested free server