You need to do two things: start being more selective about what you pick up and sell what you've already picked up.
I'm surprised you have made it to level 49 and are still storing things in Riverwood. You need to stop doing that. Go to Whiterun and buy Breezehome from the Jarl's steward. Then go to the stables outside of Whiterun, buy yourself a horse, and travel back to Riverwood. Sell a few items of jewelry at the Riverwood Trader (that's all he'll be able to buy), then pack everything you own, hop on the horse, and travel back to Whiterun. Encumbrance doesn't matter on a horse, hence the suggestion to buy one.
At Breezehome in Whiterun, I suggest breaking down your items in the following manner: put smithing-related items in one "box" (i.e., ores, ingots, leather/strips and whatever else I'm forgetting right now), unimproved weapons and armor in another "box", and anything that can be immediately sold in a third box. For me, items that can be immediately sold include jewelry, improved weapons and armor, and that category of items I don't need and which can't be improved. Some people like to enchant items before they're sold to increase their value. As for the rest of your vast collection of all other items Skyrim, you can obviously arrange things as you please. One of Breezehome's strengths is the number of storage containers it has which makes it easier to sort things out.
Having done this, your next step should be the alchemy/enchanting hack. I don't know what it's actually called, but it's the process whereby you create fortify enchanting potions, then go to the enchanting table (in this case the one in Dragonsreach) and craft fortify alchemy gear. At the alchemy table again, don your new fortify alchemy gear, and craft a new set of enchanting potions. Notice this set of enchanting potions will be more powerful than the first... allowing you to craft a more powerful set of fortify alchemy gear. You see where this is going. Repeat the process two, three, or four times - until you really can't do much better (for now). If you're not familiar with the ins and outs of the process, Google "Carlsguides Skyrim Enchanting".
The same applies to your Smithing skill. Once you've created the best set of fortify alchemy gear you can at your current Alchemy/Enchanting skill levels, go to your alchemy table and create some fortify smithing potions. Oh, and use the enchanting table to create fortify smithing gear as well. Don't forget that! Now we're coming to the point: back at Breezehome, pick up everything from your first box (i.e., ores, ingots, etc.) and everything from your second box (i.e., unimproved weapons/armor). Go next door, don your fortify smithing gear (note you should have FIVE fortify smithing items, not four), take a fortify smithing potion, and improve your weapons/armor at the grindstone and workbench. You may as well also churn out jewelry at the forge from your stores of silver and gold and your diamonds, emeralds, etc. Obviously you shouldn't waste your ore/ingots on crafting totally new weapons/armor; you have too many as it is.
You'll have accomplished a few happy things through this process: you'll have advanced 10+ levels in your smithing skill and 2+ character levels as well; you'll probably have increased the value (in septims) of a whole category of inventory by 15-20% (rough guess); and you'll have substantially reduced the ore, ingots, and gemstones in your possession. Lumber to the blacksmith and his apprentice and sell what you can, and then lumber up to Skyforge and sell what you can there, too. Later, you should craft a fortify barter necklace. For now, lumber back to Breezehome and deposit your improved weapons/armor and new set of jewelry into your "sales box" for later sales runs. Merchants' cash/inventory reset every 48 hours.
This is how you START reining in your out-of-control inventory levels.
From here, you would be wise to purchase additional homes. I suggest Honeyside in Riften as your second home. If you have completed the Thieves Guild questline and have also activated all four merchants in the Ragged Flagon, you'll have access to twice the usual number of merchants in Riften as in other cities. This combined with the three perks in the Speech skill tree that relate to increasing the amount of cash merchants have to spend and expanding their product offerings will greatly serve you in your quest to deplete excess stock. When you're ready, pack up maybe half your junk, hop on the horse, and ride to Riften. Then maybe expand to Windhelm, and to Solitude, and Markarth, and elsewhere. By the time you've reached this stage, you won't have an excess inventory problem any more, unless you keep picking up everything you see; what you'll have are smartly set up little business centers in every major town in Skyrim... and you'll be hoarding septims instead!