I have been trying to sync my wallet with the network for around 3 months, and it is still only at 45.29%. Any ideas?

I am using Bitcoin Core version v0.15.0.1 (64-bit). I have UPnP enabled, I am also port forwarding on 8333. The machine is a macbook pro running sierra 10.12.1. The wallet is on an external HDD.

I can not get more that 7 active connections to the network. Most of the time I only have 1.

I would have give up on this if I hadn’t accidentally sent bitcoins that I have mined to this address already, before the sync completed. ( I had no idea I would have these problems, I have, in the past, sync’d with no problems, using the same machine, same internet provider).

Any ideas on how I retrieve my lost coin, or make the sync process possible? I’ve exhausted the few ideas I had.

Thanks. Pete