That's not bad. Height is king in striking arts, but you're no midget
One of the golden rules of boxing/MT: unless you're planning to fight on the inside
"if you're in range, throw. otherwise get the fuck out of range"
- Grey Steel said above: "If he is busy defending he can't strike effectively. Move in with a plan of action and don't hold back." <-- I am almost 100% sure the reason you get hit is because you go in, throw something weak and then stay there. Don't stay in range! If you're moving in, throw HARD. And then get out.
People are always wondering
"how can I defend strikes by blocking/parry/slip" Here's a way easier defense at this stage - just don't be there to be hit. Get the fuck out! Works every time

Floyd Mayweather is the (sometimes self proclaimed) best boxer in the world and all this guy does most of the time is take potshots and get out of range, but look how he picked apart his opponents.
The reason is because striking is all about distance and timing really. You can punch faster than it's humanly possible to react, so people don't dodge and do defenses like in the movies (except maybe Roy Jones Jr. lol) - they are aware of when they become in range (and thus in danger) of their opponent as well as their opponent's rhythm and striking style, and this is why gives pro fighters the ability to dodge, not just purely reactions.
So when you spar,
try hard to learn your distance and timing.
- Get a feel for what your reach is, and what your partner's reach is. Make a mental note of that "danger zone"
- Get a feel for your partner's timing: what combos does he like to throw and how fast, what interval between each punch in the combo? How long after you throw does he wait to throw back? etc. etc.