What are you thinking for your immune system? Have you been diagnosed with a compromised immune system or do you just get sick a lot?

Theres a lot of reasons you can have a weakened or compromised immune system without pointing the blame at something like drugs or medication. In fact, it is much more likely the result of an underlying illness or condition than a drug interaction.

Not to say its unheard of, recently I heard of a friend of a friend getting parkinson's symptoms after receiving a rabies vaccine, and the person is only in their 20s

Smoking weed will increase the likelihood of infections in the lungs and throat, usually in the form of bronchitis. With a heavy regiment of these drugs(Anti-depressants) you could possibly jeopardize the health of your heart simply because bacterial infections in the lungs usually lead to infections in the heart. This is a direct cause because long time smokers suffer heart attacks from bacterial plaque buildup in aortic heart valves.

Since you are probably young your immediate chances of developing bacterial infections are significantly lower than someone who is a child or elderly. If you heavily abuse anti-depressants you could also suffer from depression, and youth actually increases the chances of suicide with anti-depressant withdrawal.

The drug itself doesn't present any immune issues, however frequent abuse of marijuana and antidepressants can cause acute heart issues, namely heart attack or cardiac arrest.