To address each of your concerns in turn:

I have high pitch voice.

I very much doubt this is a problem, but it's obviously something you are self-conscious about.

When I get stressed ( which happens when I am in meetings) I loose words and dont know what to say.

The best thing you can do to combat this is to ensure that you go into meetings very well prepared. The more prepared you are, the less likely that you will get nervous about what you are going to say.

Taking my technical role, my terms are technical and not clear.

This is part of your meeting preparation. Find ways to describe what you are doing in a way that is appropriate to your audience. Unless they need to know the technical details, explain what your role does in terms of the outcomes for the people in the meeting.

I am tall and dont have friendly face features.

Again, I think this is more that you are worried about it than anyone else.

Remember, you got good feedback from your manager, so most of the things you are doing are right. It really sounds like your biggest issue is not really preparing as fully as you could for these meetings, and then you tend to withdraw and stumble. Take the time to do more preparation for those meetings, in particular, who else will be attending, and try to focus your discussions in terms and language that is appropriate for them.

To address each of your concerns in turn:

I have a high pitched voice.

I very much doubt this is a problem, but it's obviously something you are self-conscious about.

When I get stressed (which happens when I am in meetings) I lose words and don't know what to say.

The best thing you can do to combat this is to ensure that you go into meetings very well prepared. The more prepared you are, the less likely that you will get nervous about what you are going to say.

Taking my technical role, my terms are technical and not clear.

This is part of your meeting preparation. Find ways to describe what you are doing in a way that is appropriate to your audience. Unless they need to know the technical details, explain what your role does in terms of the outcomes for the people in the meeting.

I am tall and don't have friendly face features.

Again, I think this is more that you are worried about it than anyone else.

Remember, you got good feedback from your manager, so most of the things you are doing are right. It really sounds like your biggest issue is not really preparing as fully as you could for these meetings, and then you tend to withdraw and stumble. Take the time to do more preparation for those meetings, in particular, who else will be attending, and try to focus your discussions in terms and language that is appropriate for them.