Well guys, it's been a long time, but I'm finally done! Thanks to everyone for your help, and Tarzanman your non carpenter's opinion was right, the joints were not strong enough, I had to add supports.
NOTE: THE SAWHORSE IS NOT PERMANENT. I AM GOING TO BUILD A SIMILAR THING BUT TIP PROOF
Here's how it turned out:
5 foot height
7 foot height (pic taken earlier so a few things are missing)
With some perspective (without ramp part)
Thank you all so much for helping me. I've had fun building it, and am going to have a lot more using it!