Withdrawal Symptoms

If I forget to take my tablet (75mg) for a few days (3-4 days) I get these pounding headaches, and I seem to get really light headed, I'm now unable to go without my tablets even for a day now, if I don't take them the symptoms above happen, but I also get really angry, and I lose my temper a lot. It's either Angry or super Depressed.
It depends how long I haven't took it for.
I'm 16 years old, I was put on Venlafaxine by my Psychiatrist, he prescribed me it because Fluoxotine didn't work with me. I tried it for 3 Months.
He then decided to put me on Venlafaxine when I was 15, and I've been on it ever since.
I still have my case of Suicidal thoughts, and I did do self-harm as well, but I haven't done that in about 7 months.

The doctor is thinking of taking me off Venlafaxine altogether this month, I don't think that's a very good idea, as I don't think very much has changed since I was first Prescribed with Severe Depression.

I've also noticed that I've put on quite a lot of weight, I try as hard as I can to lose it, but it just doesn't seem to be going away.

Do you think this is because of the Tablets I'm on?

If anyone has anything to say, please could you answer this question. I'd like to know other peoples Symptoms of when they were on Venlafaxine?

Thank you.